[{"content":"Interphase heterogeneity, rather than bulk conductivity, now limits rate capability and reversibility across lithium-metal, sodium-ion and solid-state systems.\nRecent work on lithium negative electrodes shows that dual-additive formulations shift SEI composition toward inorganic-rich layers, yet the spatial distribution of those layers remains difficult to control. Operando spectroscopic ellipsometry on lithium-metal anodes reveals pronounced non-uniform passivation that develops within the first few cycles, directly affecting local current density. Parallel simulation efforts attempt to predict interphase chemistry from electrolyte composition, but still require experimental calibration of solvation and decomposition pathways. Sodium-ion studies add another dimension: scandium incorporation and multi-element nanoscale doping alter electrode durability, yet the link to cathode-electrolyte interphase stability is not yet quantified at the particle surface. These threads converge on the same practical constraint: without spatially resolved interphase data, electrolyte and additive design remain largely empirical.\nThe strongest mechanistic signal this week is the repeated observation that uniform inorganic SEI formation is hindered by local variations in solvation structure and surface reactivity. Operando ellipsometry supplies direct evidence of thickness and optical-property gradients across the lithium surface, while dual-additive papers report changes in SEI inorganic fraction without equivalent spatial maps. Simulation work highlights the absence of transferable force fields that capture both anion coordination and decomposition kinetics at realistic electrode potentials. Until these measurements are combined on the same electrolyte systems, claims that a given additive produces a “stable” interphase stay provisional.\nThe essentials Dual-additive SEI engineering. A dual-additive approach produces an inorganic-rich solid electrolyte interphase on lithium negative electrodes, with the mechanism tied to altered solvation and selective decomposition. The evidence centers on surface analysis showing increased inorganic content, yet the paper does not resolve whether the layer remains uniform under high-rate conditions or across different current collectors.\nOperando passivation mapping. Spectroscopic ellipsometry performed during lithium-metal cycling detects non-uniform growth of the passivation layer from the earliest cycles. This spatial variation directly influences local charge-transfer resistance and is not captured by average-thickness measurements or ex-situ spectroscopy.\nInterphase prediction via simulation. A combined polarizable force-field and machine-learning approach is used to forecast interphase products on lithium metal from electrolyte composition. The unresolved step is experimental validation against operando data for the same solvent-salt-additive combinations, limiting immediate transfer to electrolyte design.\nScandium-modified sodium electrodes. Scandium addition is shown to improve durability of sodium-ion battery electrodes through changes in transport kinetics and surface stability. The mechanistic connection to cathode-electrolyte interphase formation or transition-metal dissolution remains unexamined in the reported experiments.\nNonflammable potassium electrolytes. Anion-reinforced solvation structures enable nonflammable electrolytes for potassium-ion cells while maintaining strong cation coordination. The open question is whether the same solvation motif produces a stable, inorganic-rich interphase on potassium metal or only on the cathode side.\nMechanism and evidence The clearest mechanistic advance lies in the demonstration that SEI spatial uniformity is governed by local solvation heterogeneity rather than average coordination strength. Operando ellipsometry supplies the first direct, time-resolved map of thickness gradients on lithium metal, linking early-cycle non-uniformity to subsequent current constriction. Dual-additive studies show that targeted anion decomposition can increase the inorganic fraction, but without spatially resolved follow-up the functional benefit at high rate stays correlative. Simulation frameworks now attempt to close the prediction gap, yet they still lack validated decomposition pathways at the potentials and concentrations used in the experimental papers. The combined evidence points to a need for coupled operando and modeling studies on identical electrolyte formulations.\nMaterials and interfaces Cathode and anode interface work this week centers on surface modification and solvation control. Surface-fluorinated conductive carbon is examined for coupled electron-ion transport at graphite, while gel-polymer and polymer electrolytes incorporating fluorine and phosphorus are tested for selective ion transport in lithium-metal cells. On the sodium side, multi-element nanoscale doping of iron-rich layered oxides and scandium incorporation aim at electrode-level durability. Solid-state sulfide electrolytes synthesized via liquid-phase routes are reported for lithium-sulfur cells, but interfacial contact and chemo-mechanical stability data are not yet linked to the interphase heterogeneity observed in liquid systems.\nScale-up, safety and manufacturing Safety-related studies emphasize design-level constraints over material claims. Replaceable covers combined with oil cooling are explored to improve thermal management and post-accident handling of EV battery packs, addressing both mechanical access and heat extraction. Calendar-aging investigations highlight that most cells spend the majority of their life at rest, yet few datasets quantify how interphase evolution during storage affects subsequent cycle life. Nonflammable electrolyte formulations for potassium systems offer a route to reduced fire risk, but the translation to large-format cells requires stack-pressure and separator compatibility data that remain outside the current reports.\nQuick Radar Liquid-phase synthesis of superionic sulfide electrolytes: Targets all-solid-state lithium-sulfur cells, yet critical current density and interfacial void formation under stack pressure are not addressed. Ambient-stable cathode-level solid electrolyte: Achieved via wetting-controlled surface modification, raising the question of compatibility with dry-electrode processing routes. Semi-solid anode-free Cu-Li2S cell: Combines Li6PS5Cl with a solvate ionic liquid; the effect of the liquid component on interfacial contact resistance over cycling is unresolved. Cation-polymer coordination in gel polymer electrolytes: Tuned for sodium metal batteries, but sodium plating morphology and dead-sodium accumulation data are absent. Predictive frequency-domain sampling methods: Proposed for spatiotemporal battery modeling, yet their accuracy for interphase growth kinetics has not been benchmarked against operando measurements. Closing The practical question for the coming week is whether any of the reported additive or doping strategies can be shown to reduce spatial gradients in interphase thickness when tested under identical current-density and temperature conditions.\nSources Nature Portfolio - Batteries: Dual-additive enabled inorganic-rich solid electrolyte interphase for high-rate lithium negative electrodes - https://www.nature.com/articles/s41467-026-76653-7 EKL Batteries: Reveal Non-Uniform Passivation on Lithium Metal Anode With Operando Spectroscopic Ellipsometry - https://advanced.onlinelibrary.wiley.com/doi/10.1002/aenm.71434?af=R arXiv - Battery interphase query: Predictive Simulation of Interphases on Li Metal Surface - https://arxiv.org/abs/2608.09791v1 Tech Xplore - Energy \u0026amp; Green Tech: How scandium can improve the durability of sodium-ion battery electrodes - https://techxplore.com/news/2026-08-scandium-durability-sodium-ion-battery.html Nature Portfolio - Batteries: Multi-element nanoscale doping of iron-rich sodium layered oxides enables ampere-hour-level Na-ion batteries - https://www.nature.com/articles/s41565-026-02257-3 EKL Batteries: Surface-Fluorinated Conductive Carbon for Coupled Electron/Ion Transport Through the Graphite Anode - https://advanced.onlinelibrary.wiley.com/doi/10.1002/aenm.71436?af=R Nature Portfolio - Batteries: Reconciling strong coordination and anion-reinforced solvation structure enables nonflammable electrolytes for potassium-ion batteries - https://www.nature.com/articles/s41467-026-76791-y Tech Xplore - Energy \u0026amp; Green Tech: New engineering studies aim to slow battery aging while idle - https://techxplore.com/news/2026-08-aim-battery-aging-idle.html Tech Xplore - Energy \u0026amp; Green Tech: Replaceable covers and oil cooling could make EV batteries safer and easier to repair - https://techxplore.com/news/2026-08-oil-cooling-ev-batteries-safer.html ","permalink":"https://interphasebrief.com/newsletter/2026-w34/","summary":"\u003cp\u003eInterphase heterogeneity, rather than bulk conductivity, now limits rate capability and reversibility across lithium-metal, sodium-ion and solid-state systems.\u003c/p\u003e\n\u003cp\u003eRecent work on lithium negative electrodes shows that dual-additive formulations shift SEI composition toward inorganic-rich layers, yet the spatial distribution of those layers remains difficult to control. Operando spectroscopic ellipsometry on lithium-metal anodes reveals pronounced non-uniform passivation that develops within the first few cycles, directly affecting local current density. Parallel simulation efforts attempt to predict interphase chemistry from electrolyte composition, but still require experimental calibration of solvation and decomposition pathways. Sodium-ion studies add another dimension: scandium incorporation and multi-element nanoscale doping alter electrode durability, yet the link to cathode-electrolyte interphase stability is not yet quantified at the particle surface. These threads converge on the same practical constraint: without spatially resolved interphase data, electrolyte and additive design remain largely empirical.\u003c/p\u003e","title":"Interphase Brief - Week 34, 2026"},{"content":"Electrolyte solvation, interphase formation, and solid-electrolyte contact emerge as coupled limits on fast-charge stability and solid-state viability rather than independent optimization targets.\nFast charging of lithium-ion cells repeatedly drives lithium plating when the anode-electrolyte interface cannot sustain the required lithium-ion flux without metallic deposition. The supplied reports examine whether changes in solvent coordination or additive behavior can shift the onset of plating by altering the local concentration gradient and the composition of the forming interphase. Parallel work on sodium-metal and zinc systems tests whether the same solvation and corrosion mechanisms appear once the alkali or divalent cation replaces lithium. In solid-state configurations, the question moves from solvent coordination to particle-to-particle contact and the mechanical integrity of the interface under stack pressure.\nThese threads converge on a shared experimental gap: most measurements still separate transport kinetics from long-term interfacial evolution. Calendar aging, cycling-induced cracking, and moisture sensitivity each alter the very layers that are meant to stabilize the cell, yet few studies report both the initial solvation structure and the post-mortem interphase chemistry under identical conditions. The practical consequence is that claims of improved rate capability remain difficult to translate into cell-level retention when temperature, pressure, or electrolyte volume change.\nThe essentials Fast-charge lithium plating mitigation. Reports describe solvent and additive strategies intended to raise the threshold current at which metallic lithium appears on graphite or silicon anodes. The mechanistic claim centers on reduced concentration polarization and altered SEI growth kinetics, yet the supplied accounts give no post-mortem evidence that the new interphase survives repeated fast-charge cycles without progressive thickening or loss of lithium inventory.\nSodium-metal solvent coordination. Work from MIT and its Tech Xplore summary isolates the role of residual solvent in promoting continuous corrosion of sodium anodes. The central observation is that solvent molecules remaining after salt dissociation accelerate parasitic reactions during both cycling and storage; the unresolved question is whether complete solvent removal can be achieved without sacrificing ionic conductivity or introducing new passivation layers.\nDilute electrolytes in aqueous zinc cells. Nature Communications papers examine dilute formulations that suppress zinc corrosion during calendar aging and cycling. The evidence links lower free-water activity to reduced hydrogen evolution and more uniform deposition, but the reports leave open how these electrolytes behave once zinc loading increases or when the cell is held at elevated temperature for extended periods.\nSulfide solid-electrolyte refinement. Two Nature Communications articles address mechanical milling and surface protection of sulfide electrolytes to improve interfacial contact with lithium metal. The data focus on reduced impedance and improved critical current density, yet the accounts do not report whether the refined powders retain their conductivity after exposure to trace moisture or after repeated stack-pressure cycling.\nLLZO phase and transport characterization. An arXiv preprint combines molecular-dynamics Raman calculations with experiment to link spectral features in LLZO to lithium-ion site occupancy and mobility. The work clarifies why cubic and tetragonal phases differ in conductivity, but it remains unclear how the same Raman signatures evolve once an interphase forms between LLZO and lithium metal under applied current.\nMechanism and evidence The strongest mechanistic signal this week is the repeated demonstration that solvent or additive molecules directly participate in the early stages of interphase growth rather than acting only as inert carriers of ions. In both non-aqueous lithium and aqueous zinc systems, the evidence points to specific coordination changes that alter the reduction or oxidation potential at the electrode surface. The quality of that evidence is still largely spectroscopic or electrochemical; few of the cited studies combine operando interface probes with post-cycle chemical mapping on the same cells. This leaves open whether the observed solvation changes persist once the interphase thickens or cracks.\nMaterials and interfaces Cathode-anode pairing and electrolyte choice remain tightly coupled through the interphase. Sodium-metal work highlights residual solvent as a persistent source of corrosion, while zinc studies show that diluting the electrolyte reduces free-water activity at the metal surface. In solid-state systems, the focus shifts to particle perimeter contact and protective interlayers between halide or sulfide electrolytes and the active material. The common limitation is that none of the reports quantify how these interfacial layers evolve when stack pressure, temperature, or current density deviate from the laboratory test conditions.\nScale-up, safety and manufacturing Solid-state patent filings emphasize graded wetting agents and ion-conducting interlayers to achieve high cathode-particle contact, yet the manufacturing route still requires control of moisture and particle dispersion that has not been demonstrated at pilot scale. Aqueous zinc and dilute-electrolyte approaches raise separate questions about water management and corrosion-product accumulation over thousands of cycles. No report supplies cell-level data that link these interface modifications to thermal-runaway thresholds or to retention after formation at realistic electrolyte volumes.\nQuick Radar BYD patents: Describe graded ionic-liquid wetting and ion-conducting interlayers for sulfide electrolytes but supply no cycling data under defined stack pressure. Raman-MD calculations on LLZO: Clarify phase-dependent lithium dynamics yet do not address interphase growth under applied current. ZIF glass electrolytes: Reported to enable isotropic lithium diffusion, but grain-boundary-free behavior after moisture exposure remains untested. Reflex charging protocols: Proposed to form anion-derived SEI layers, yet the dependence on cell format and electrolyte volume is not reported. Dilute zinc electrolytes: Reduce calendar corrosion, but the effect of zinc loading and temperature on long-term water activity is unresolved. Mechanical refinement of sulfide electrolytes: Lowers impedance, but moisture sensitivity after milling is not quantified. Sodium-metal solvent studies: Isolate residual-solvent corrosion yet leave open whether complete desolvation compromises conductivity at low temperature. Closing The recurring experimental gap is whether solvation or contact improvements identified in half-cells survive the combined stresses of full-cell formation, stack pressure, and calendar aging; readers may usefully ask which of their own test protocols would reveal that gap first.\nSources EKL Batteries: Reflex Charging for Anion-Derived Solid Electrolyte Interphase Formation - https://onlinelibrary.wiley.com/doi/10.1002/anie.4035251?af=R MIT News - Batteries: Solving the solvent problem - https://news.mit.edu/2026/solving-solvent-problem-sodium-metal-batteries-0804 Tech Xplore - Energy \u0026amp; Green Tech: New strategy for designing ultra-fast charging batteries could prevent hazardous lithium plating - https://techxplore.com/news/2026-08-strategy-ultra-fast-batteries-hazardous.html Tech Xplore - Energy \u0026amp; Green Tech: Solving the solvent problem to make sodium-metal batteries a more practical energy storage option - https://techxplore.com/news/2026-08-solvent-problem-sodium-metal-batteries.html arXiv - Battery electrolytes query: Raman Signatures of Lithium Ion Dynamics in LLZO Garnet Electrolytes: Atomistic Insights from MD-Raman Calculations - https://arxiv.org/abs/2608.04690v1 Nature Portfolio - Batteries: Dilute electrolytes for suppressing metal anode corrosion during calendar aging and cycling in aqueous zinc batteries - https://www.nature.com/articles/s41467-026-75100-x EKL Batteries: Mechanistic Mapping of Additive Cracking for Hybrid SEI Construction in Aqueous Zinc-Ion Batteries - https://advanced.onlinelibrary.wiley.com/doi/10.1002/adfm.77591?af=R Nature Portfolio - Batteries: Anisotropy-mediated stress regulation in Mn-substituted VOPO4 enables aqueous zinc batteries with long cycle life - https://www.nature.com/articles/s41467-026-74444-8 ","permalink":"https://interphasebrief.com/newsletter/2026-w33/","summary":"\u003cp\u003eElectrolyte solvation, interphase formation, and solid-electrolyte contact emerge as coupled limits on fast-charge stability and solid-state viability rather than independent optimization targets.\u003c/p\u003e\n\u003cp\u003eFast charging of lithium-ion cells repeatedly drives lithium plating when the anode-electrolyte interface cannot sustain the required lithium-ion flux without metallic deposition. The supplied reports examine whether changes in solvent coordination or additive behavior can shift the onset of plating by altering the local concentration gradient and the composition of the forming interphase. Parallel work on sodium-metal and zinc systems tests whether the same solvation and corrosion mechanisms appear once the alkali or divalent cation replaces lithium. In solid-state configurations, the question moves from solvent coordination to particle-to-particle contact and the mechanical integrity of the interface under stack pressure.\u003c/p\u003e","title":"Interphase Brief - Week 33, 2026"},{"content":"Interface stability under realistic exposure and cycling conditions remains the dominant constraint in solid-state systems, where moisture attack, mechanical ductility, and SEI growth kinetics must be treated as coupled variables rather than isolated material properties.\nThe supplied reports this week converge on two practical questions. First, how does trace moisture under dry-room conditions alter the surface chemistry of sulfide electrolytes such as argyrodite Li6PS5Cl, and what spatial resolution is required to map the resulting degradation products? Second, whether existing models of SEI growth can be made to respect physical rate laws across varying protocols without overfitting to single datasets.\nThese questions matter because dry-room processing is already the industrial baseline, and any moisture-driven surface reconstruction directly affects critical current density and stack-pressure requirements. Modeling frameworks that embed Arrhenius kinetics for SEI growth and lithium inventory loss offer one route to test consistency, yet they still require validation against spatially resolved post-mortem data.\nThe essentials Moisture-driven surface changes in argyrodite. A study maps the chemical evolution of Li6PS5Cl surfaces when exposed to controlled humidity levels representative of dry-room environments, showing that even low moisture partial pressures produce detectable surface species that alter interfacial impedance.\nCorrection on SEI mechanical properties. An author correction to earlier work on a ductile solid electrolyte interphase clarifies the mechanical characterization conditions and the extent to which ductility claims depend on specific electrolyte formulations and cycling parameters.\nPhysics-informed SOH modeling. The PiDDM framework incorporates empirical Arrhenius terms for SEI growth and lithium inventory loss directly into the training loss, reducing physically implausible extrapolation on a public dataset of 55 cells cycled under varied conditions.\nSpatially resolved diffraction for degradation mapping. A μ-XRD workflow applied to inhomogeneous polycrystalline samples demonstrates how hundreds of micron-scale diffraction patterns can be processed to extract local phase fractions and strain distributions linked to degradation.\nPolymer electrolyte solvation control. Work on quasi-solid-state sodium metal cells shows that tuning the solvation structure within a polymer matrix improves interfacial stability, although the precise balance between ionic transport and reductive stability at the sodium surface remains to be quantified.\nMechanism and evidence The clearest mechanistic signal concerns moisture attack on sulfide surfaces. The argyrodite study isolates the chemical steps that convert Li6PS5Cl into surface phosphates or oxides under dry-room humidity, directly linking these products to increased charge-transfer resistance. Evidence quality is moderate: the work reports surface-sensitive measurements but does not yet provide full cell-level cycling data under the same exposure conditions. Complementary μ-XRD work supplies a route to map the spatial extent of such degradation products inside composite electrodes, yet the analysis pipeline still requires manual intervention for phase identification across thousands of patterns. The PiDDM approach tests whether embedding known SEI kinetics improves long-term extrapolation, but its performance on solid-state rather than liquid systems is not addressed.\nMaterials and interfaces Surface reconstruction of argyrodite and the mechanical properties of the resulting interphase dominate the interface discussion. The correction to the ductile-SEI paper underscores that measured ductility can depend on the precise stack pressure and temperature window used during testing, limiting direct transfer to other sulfide or oxide systems. Polymer-electrolyte work on sodium cells points to solvation-sheath engineering as a lever for reducing continuous SEI growth, yet the trade-off between bulk ionic conductivity and the stability of the sodium-polymer boundary is not fully resolved. No new bulk cathode or anode compositions are introduced; the emphasis remains on how existing materials respond once interfaces are exposed to realistic processing or cycling environments.\nScale-up, safety and manufacturing A standardized battery database initiative highlights the inconsistency in reported metadata across thousands of published solid-state device papers, which directly limits the training of AI models intended to guide electrolyte or interface design. Without uniform reporting of cell format, stack pressure, electrolyte loading, and post-mortem conditions, cross-study comparisons remain unreliable. The hidden-flaw report on high-nickel cathodes flags a materials-level degradation pathway that could affect lifetime in cobalt-free cells, but the underlying mechanism and its dependence on electrode loading or electrolyte formulation are not detailed. No manufacturing-scale process data or safety-test results are supplied.\nQuick Radar The μ-XRD pipeline still requires substantial manual input for Rietveld refinement across variable phase mixtures. PiDDM validation is limited to liquid-electrolyte cells; extension to solid-state interfaces is not shown. Moisture-induced species on Li6PS5Cl are identified, but their effect on critical current density under applied pressure is unreported. The ductile-SEI correction leaves open whether the revised mechanical values hold across different sulfide chemistries. Polymer-electrolyte sodium cells improve interface stability via solvation tuning, yet the sodium stripping-plating overpotential window is unspecified. A proposed battery database aims to standardize metadata, but adoption criteria and minimum reporting fields are not defined. Thermal-runaway modeling for large-face liquid-cooled packs addresses propagation, yet the cell-to-cell variability in onset temperature remains unquantified. Closing The practical question for the coming week is whether moisture-exposure protocols used in the argyrodite study can be combined with stack-pressure cycling to produce a single, transferable metric for interfacial stability.\nSources Nature Portfolio - Batteries: Author Correction: A ductile solid electrolyte interphase for solid-state batteries - https://www.nature.com/articles/s41586-026-10945-2 Nature Portfolio - Batteries: Moisture-induced surface degradation mechanism of argyrodite Li6PS5Cl under dry-room conditions - https://www.nature.com/articles/s41467-026-75537-0 arXiv - Battery degradation query: Automating the analysis of micron-scale synchrotron diffraction data on inhomogeneous polycrystalline samples: a solid oxide electrolysis cell case study - https://arxiv.org/abs/2607.28859v1 Tech Xplore - Energy \u0026amp; Green Tech: Standardized battery database could improve AI-guided solid-state battery design - https://techxplore.com/news/2026-07-standardized-battery-database-ai-solid.html arXiv - Battery interphase query: PiDDM: Physics-Informed Differentiable Degradation Modeling for Lithium-Ion Battery State-of-Health Prediction - https://arxiv.org/abs/2607.29095v1 Tech Xplore - Energy \u0026amp; Green Tech: Hidden battery flaw may shorten EV lifespans - https://techxplore.com/news/2026-07-hidden-battery-flaw-shorten-ev.html ","permalink":"https://interphasebrief.com/newsletter/2026-w32/","summary":"\u003cp\u003eInterface stability under realistic exposure and cycling conditions remains the dominant constraint in solid-state systems, where moisture attack, mechanical ductility, and SEI growth kinetics must be treated as coupled variables rather than isolated material properties.\u003c/p\u003e\n\u003cp\u003eThe supplied reports this week converge on two practical questions. First, how does trace moisture under dry-room conditions alter the surface chemistry of sulfide electrolytes such as argyrodite Li6PS5Cl, and what spatial resolution is required to map the resulting degradation products? Second, whether existing models of SEI growth can be made to respect physical rate laws across varying protocols without overfitting to single datasets.\u003c/p\u003e","title":"Interphase Brief - Week 32, 2026"},{"content":"Solid-state and quasi-solid electrolytes are being evaluated through the lens of interfacial stability, where composition tuning, coatings, and dynamic interfaces are tested against space-charge layers, moisture sensitivity, and contact loss rather than bulk conductivity alone.\nThe arXiv preprint on Li6+xSixSb1-xS5I argyrodites starts from the known limits of iodide-based sulfides: space-charge layers at the cathode interface, slow ion transport across grain boundaries, and susceptibility to lithium penetration. The work reports a ball-milled Li6.6Si0.6Sb0.4S5I composition that aims to raise room-temperature conductivity while widening the electrochemical window. Whether the measured gains survive full-cell stack pressure, repeated plating, and post-mortem analysis of the space-charge region remains the decisive test.\nA separate Nature paper on initially anode-free quasi-solid lithium metal cells introduces dynamic interface engineering to maintain contact without external pressure. The approach couples a polymer-rich electrolyte with an adaptive interphase that responds to volume changes during stripping and plating. The central uncertainty is how the same interface behaves under the higher current densities and lean-electrolyte conditions required for practical energy density.\nCommercial reporting on Sumitomo’s halide electrolyte development highlights a different constraint: cost and processability versus sulfide benchmarks. The material is positioned as an alternative that avoids sulfur volatility while matching conductivity, yet the data needed to judge interfacial stability with high-voltage cathodes or moisture tolerance during handling are not yet public.\nThe essentials Argyrodite composition tuning The Li6.6Si0.6Sb0.4S5I electrolyte is synthesized by ball milling to alter the Si/Sb ratio and thereby modify lattice parameters and defect concentrations. The preprint links these changes to improved ionic conductivity and reduced dendrite penetration, but does not yet report critical current density under controlled stack pressure or long-term cycling with high-voltage cathodes.\nDynamic interface in anode-free cells The Nature Communications study on quasi-solid anode-free lithium metal batteries uses an integrated interface that adapts during cycling. Evidence centers on maintained contact and reduced impedance growth, yet the work leaves open how the same chemistry performs when electrolyte volume is minimized and current density is raised.\nHalide electrolyte scale-up path Sumitomo’s halide-based solid electrolyte is reported to reach sulfide-level conductivity at lower projected manufacturing cost through collaboration with Kyoto and Tottori universities. The technical signal is the shift from sulfide to halide chemistry; unresolved questions concern interfacial reactions with oxide cathodes and moisture stability during electrode processing.\nDiffusivity measurement practices The arXiv perspective on battery material comparisons argues that 49% of recent transport claims rely on diffusivity values, yet only 15% of those clearly state how the active-material length scale was measured. The paper calls for consistent surface-area protocols before structure-property conclusions are drawn across solid electrolytes.\nElectrode thickness mapping for safety A KAIST method detects nanoscale electrode thickness variations without cell disassembly, targeting defects that can initiate thermal runaway. The approach supplies spatially resolved data at manufacturing scale, but its sensitivity to buried interfaces inside full solid-state stacks is not yet demonstrated.\nMechanism and evidence The strongest mechanistic thread is the repeated focus on space-charge layers and contact loss rather than bulk conductivity. The argyrodite preprint and the anode-free quasi-solid study both identify interfacial ion depletion and mechanical decoupling as primary failure modes. Evidence quality is highest where operando or post-mortem measurements are described; it weakens where only half-cell conductivity or short-term impedance data are shown. The diffusivity perspective adds a methodological caution: many transport claims rest on incompletely documented length-scale assumptions, which directly affects interpretation of the new electrolyte results.\nMaterials and interfaces Cathode-electrolyte compatibility remains the dominant materials question. The halide electrolyte report and the argyrodite composition work both target reduced reactivity at high-voltage interfaces, yet neither supplies detailed CEI composition or transition-metal dissolution data. The organic coating work on sulfide electrolytes (noted in secondary sources) points to moisture protection as an additional requirement that must be solved without blocking ion transport. Quasi-solid systems introduce polymer-ceramic interphases whose solvation structure and mechanical compliance are still being mapped.\nScale-up, safety and manufacturing Electrode thickness uniformity emerges as a concrete manufacturing constraint. The KAIST scan method offers a non-destructive route to detect variations that could seed thermal runaway, yet its applicability inside solid-state stacks with rigid interfaces is untested. Halide electrolyte processing is presented as lower-cost, but the handling requirements for moisture-sensitive powders and the compatibility with dry-electrode routes remain open. Safety-focused work on AI data-center installations underscores the need for validated thermal-runaway thresholds under high-frequency cycling, independent of chemistry marketing claims.\nQuick Radar Diffusivity assumptions: The arXiv diffusivity perspective questions whether 85% of reported transport values rest on unverified length-scale assumptions. Halide electrolyte stability: Sumitomo’s halide electrolyte development leaves interfacial stability with high-voltage cathodes unreported. Anode-free cycling conditions: The quasi-solid anode-free lithium study does not specify stack pressure or lean-electrolyte conditions used in cycling. Electrode-thickness mapping validation: KAIST electrode-thickness mapping has not been validated on solid-state pouch cells. Argyrodite composition data: No cell-level data link the new argyrodite composition to critical current density under sustained pressure. Closing The practical question for the coming week is whether any of the reported interfacial modifications maintain low impedance and uniform current distribution once stack pressure, electrolyte volume, and cathode loading are set to values required for \u0026gt;350 Wh kg-1 cells.\nSources arXiv - Solid-state batteries query: Synergistic Interface Stability and High Room-Temperature Ionic Conductivity for Wide-Temperature All-Solid-State Batteries Based on Li6+xSixSb1-xS5I Electrolytes - https://arxiv.org/abs/2607.19664v1 Batteries News: Sumitomo to mass-produce new Solid State Battery electrolyte - report - https://batteriesnews.com/sumitomo-to-mass-produce-new-solid-state-battery-electrolyte-report/ Nature Portfolio - Batteries: Highly stable quasi-solid-state initially anode-free lithium metal batteries enabled by dynamic integrated interface engineering - https://www.nature.com/articles/s41467-026-76060-y arXiv - Solid-state batteries query: Battery Material Comparisons Should Refocus on Diffusivity with Best Practices - https://arxiv.org/abs/2607.18590v1 Tech Xplore - Energy \u0026amp; Green Tech: Ultraprecise battery scan maps nanoscale electrode thickness variations to improve EV fire safety - https://techxplore.com/news/2026-07-ultraprecise-battery-scan-nanoscale-electrode.html ","permalink":"https://interphasebrief.com/newsletter/2026-w31/","summary":"\u003cp\u003eSolid-state and quasi-solid electrolytes are being evaluated through the lens of interfacial stability, where composition tuning, coatings, and dynamic interfaces are tested against space-charge layers, moisture sensitivity, and contact loss rather than bulk conductivity alone.\u003c/p\u003e\n\u003cp\u003eThe arXiv preprint on Li6+xSixSb1-xS5I argyrodites starts from the known limits of iodide-based sulfides: space-charge layers at the cathode interface, slow ion transport across grain boundaries, and susceptibility to lithium penetration. The work reports a ball-milled Li6.6Si0.6Sb0.4S5I composition that aims to raise room-temperature conductivity while widening the electrochemical window. Whether the measured gains survive full-cell stack pressure, repeated plating, and post-mortem analysis of the space-charge region remains the decisive test.\u003c/p\u003e","title":"Interphase Brief - Week 31, 2026"},{"content":"Spray deposition of compositional gradients and immobilized gel electrolytes is being examined as a route to couple ion-transport pathways with interphase stability in silicon, lithium-sulfur, and solid-state cells.\nHomogeneous slurry casting often produces uniform porosity and composition that cannot simultaneously optimize electron and ion pathways, leading to localized lithium depletion during fast charge. Ultrasonic spray methods now allow deliberate placement of porosity near the separator and carbon enrichment near the current collector, directly addressing the transport asymmetry that accelerates degradation. Parallel work on UV-cured gel films deposited in the same manner replaces free liquid with a thin, pinhole-free polymer layer that can be formed directly on the graded electrode. These approaches shift the design problem from bulk electrolyte properties toward controlled spatial variation of both microstructure and interphase chemistry.\nThe same spray platform is being applied to moisture-sensitive solid-state systems inside glovebox environments, raising questions about how droplet size, drying kinetics, and substrate temperature interact with salt solubility and polymer curing. Evidence remains largely at the electrode or half-cell level; full-cell data under stack pressure and defined temperature windows are still required to judge whether the gradients survive repeated volume changes.\nThe essentials Graded electrode microstructures via ultrasonic spray A UCL thesis demonstrates spray deposition that places higher porosity at the separator-facing side and carbon enrichment at the current-collector side in lithium-sulfur, solid-state, and silicon electrodes. The resulting asymmetry is intended to mitigate uneven lithium depletion during fast charge. Post-mortem evidence linking the gradient to reduced loss of lithium inventory is still needed.\nUV-cured gel polymer films on graded electrodes An ACS Omega study reports ultrasonic spray of a low-viscosity methyl-methacrylate precursor followed by in-place UV curing to produce thin, pinhole-free gel layers. The process eliminates free liquid and the conventional separator while enabling direct formation of an artificial interphase on the electrode. Roll-to-roll compatibility and material utilization above 95% are claimed, yet long-term adhesion under cycling-induced volume change remains untested at the cell level.\nPhase-field modeling of dendrite asymmetry in sodium solid-state cells An arXiv preprint applies a phase-field model informed by DFT to polycrystalline Na₃SbS₄ with either pure sodium or Na-Sb alloy anodes. The simulation shows that dendrite stripping during discharge is intrinsically asymmetric, leaving residual filaments that promote re-penetration on the next charge. Experimental validation of the predicted filament morphology under varying stack pressure is still absent.\nNonflammable electrolyte with altered Li⁺ desolvation A Nature Communications paper examines a nonflammable formulation whose solvation structure accelerates Li⁺ desolvation at the interface. The work links this change to improved high-voltage stability and reduced thermal-runaway risk, but does not report whether the same solvation modification can be maintained inside a sprayed gel matrix.\nSpray-based immersion cooling under fast-charge conditions A Tech Xplore report describes a dielectric-liquid spray system that maintains stable pack temperatures during fast charge while cutting liquid consumption by roughly 85% relative to full immersion. The approach addresses heat removal at the cell surface but does not yet address internal temperature gradients created by the graded electrodes described above.\nMechanism and evidence The strongest mechanistic signal is the deliberate spatial decoupling of ionic and electronic pathways through porosity and carbon gradients. Spray deposition supplies the spatial resolution that slurry casting lacks, yet the supporting data are still dominated by ex-situ imaging and single-electrode cycling. No study in the current set provides operando visualization of lithium concentration profiles inside a full cell that contains both a graded electrode and a sprayed gel layer. Without such measurements, the link between the engineered gradient and reduced loss of lithium inventory remains inferential.\nMaterials and interfaces Several electrolyte-design papers emphasize rigid polyanions or balanced solvation to raise lithium transference and suppress anion decomposition. These molecular-level changes are complementary to the spray-deposited architectures, but integration has not been demonstrated. Silicon-anode binder work focuses on interfacial-mechanical coupling, yet none of the reported binders has been tested on the carbon-rich collector side of a sprayed gradient electrode. Solid-state sodium modeling highlights the role of grain boundaries in dendrite propagation, an issue that sprayed interphase layers might mitigate if they can conformally coat polycrystalline surfaces.\nScale-up, safety and manufacturing Ultrasonic spray offers high material utilization and glovebox compatibility for moisture-sensitive salts, but the requirement for multiple passes and precise droplet control introduces new process variables whose effect on defect density at square-meter scale is unknown. Spray cooling reduces external fire risk under fast charge, yet internal heat generation within a graded electrode still depends on the local tortuosity created by the deposition process. No study quantifies how residual solvent or incomplete curing in the gel film would alter thermal-runaway thresholds.\nQuick Radar Phase-field model for Na₃SbS₄: Predicts asymmetric dendrite stripping; the next required measurement is whether residual filaments persist after full discharge at defined stack pressure. Spray-deposited gel films: Eliminate the separator yet introduce a new failure mode if pinholes form during roll-to-roll curing. Nonflammable electrolytes: Enhanced desolvation has not been evaluated inside polymer matrices deposited by the same ultrasonic method. Graded silicon electrodes: Place carbon enrichment at the current collector; the mechanical integrity of this interface under repeated expansion remains unquantified. Spray cooling: Reduces liquid volume but does not address whether internal temperature gradients in graded electrodes exceed the external cooling rate. Amino-silane bridging in polymer-ceramic composites: Improves interfacial compatibility; compatibility with spray-deposited electrodes has not been tested. Bacterial-cellulose-derived carbons: Proposed for supercapacitors; their tortuosity when used as conductive additives in sprayed battery electrodes is unknown. Closing The practical question for the coming week is whether the transport benefit of a porosity gradient survives when the same electrode is paired with a sprayed gel electrolyte under realistic stack pressure and temperature.\nSources Nature Portfolio - Batteries: High-voltage and high-safety lithium-ion batteries enabled by nonflammable electrolyte with enhanced Li+ desolvation behavior - https://www.nature.com/articles/s41467-026-75482-y Nature Portfolio - Batteries: Fast lithium-ion transport in polymer electrolytes with rigid polyanions - https://www.nature.com/articles/s41565-026-02229-7 Tech Xplore - Energy \u0026amp; Green Tech: Finding the sweet spot for safer, longer-lasting lithium metal batteries - https://techxplore.com/news/2026-07-sweet-safer-longer-lithium-metal.html arXiv - Solid-state batteries query: Phase-Field Simulation of Dendrite Evolution in All-Solid-State Sodium Batteries during Cycling - https://arxiv.org/abs/2607.15387v1 Tech Xplore - Energy \u0026amp; Green Tech: Enhancing battery safety under fast charging conditions through spray-based immersion cooling - https://techxplore.com/news/2026-07-battery-safety-fast-conditions-spray.html Nature Portfolio - Batteries: Synergistic interfacial-mechanical binder design for high-areal-capacity and long-lifespan Si-based negative electrodes in practical pouch cells - https://www.nature.com/articles/s41467-026-75167-6 ","permalink":"https://interphasebrief.com/newsletter/2026-w30/","summary":"\u003cp\u003eSpray deposition of compositional gradients and immobilized gel electrolytes is being examined as a route to couple ion-transport pathways with interphase stability in silicon, lithium-sulfur, and solid-state cells.\u003c/p\u003e\n\u003cp\u003eHomogeneous slurry casting often produces uniform porosity and composition that cannot simultaneously optimize electron and ion pathways, leading to localized lithium depletion during fast charge. Ultrasonic spray methods now allow deliberate placement of porosity near the separator and carbon enrichment near the current collector, directly addressing the transport asymmetry that accelerates degradation. Parallel work on UV-cured gel films deposited in the same manner replaces free liquid with a thin, pinhole-free polymer layer that can be formed directly on the graded electrode. These approaches shift the design problem from bulk electrolyte properties toward controlled spatial variation of both microstructure and interphase chemistry.\u003c/p\u003e","title":"Interphase Brief - Week 30, 2026"},{"content":"Grain boundaries and solid-solid interfaces, rather than bulk conductivity, set the practical limits on dendrite formation, lithiation uniformity, and interphase stability in solid-state and high-voltage systems.\nSolid-state electrolytes were expected to eliminate liquid-related safety risks while supporting higher energy density. In practice, lithium filaments still appear at internal boundaries where two grains of electrolyte meet. The MIT study isolates these grain boundaries as nucleation sites because they locally alter the electric field and provide fast diffusion paths that concentrate lithium. This shifts attention from electrode-electrolyte contact alone to the polycrystalline microstructure itself.\nHigh-Ni layered oxides face a parallel constraint at the particle scale. Grain boundaries inside the cathode active material become sites of electrolyte infiltration and mechanical degradation once the cell reaches high voltage. An elastomeric interphase grown in situ is reported to coat these internal surfaces and reduce cracking, yet the long-term stability of that coating under repeated lattice expansion remains untested at electrode loadings typical of pouch cells.\nOperando neutron imaging supplies direct spatial evidence that lithium distribution inside working solid-state cells is already inhomogeneous after the first charge. The same technique applied to liquid-electrolyte high-Ni NMC cells shows electrolyte dynamics that correlate with local state-of-charge gradients. Both observations point to transport bottlenecks at boundaries rather than average ionic conductivity.\nThe essentials Grain-boundary dendrite seeding. MIT researchers traced lithium filament initiation to electrolyte grain boundaries rather than the electrode interface, showing that local field concentration and fast diffusion along these boundaries precede short-circuit failure.\nCathode grain-boundary stabilization. An in-situ elastomeric interphase was formed on high-voltage layered-oxide particles; the coating is claimed to suppress electrolyte penetration and particle fracture, but post-mortem evidence at full electrode level and extended cycling is still required.\nNeutron imaging of lithiation heterogeneity. Operando neutron measurements on solid-state cells reveal non-uniform lithium accumulation that correlates with grain-boundary locations, while parallel imaging of high-Ni NMC cells links electrolyte dynamics to the same spatial pattern.\nReduced interfacial resistance in sodium systems. Direct growth of a Na-ion conducting solid glass electrolyte on sodium-sulfur electrodes lowers measured interfacial resistance and enables room-temperature pouch-cell operation, although critical current density and stack-pressure requirements are not reported.\nGradient-solvation electrolyte for lithium metal. A single-phase electrolyte designed with a solvation gradient is shown to stabilize lithium-metal anodes; the mechanistic link between the solvation profile and dendrite suppression still needs boundary-specific diagnostics.\nMechanism and evidence The clearest mechanistic signal is that grain boundaries inside solid electrolytes and inside cathode particles act as both ionic and mechanical weak points. Neutron imaging supplies spatially resolved lithium maps that directly correlate with these boundaries, moving the argument beyond indirect impedance or post-mortem imaging. The elastomeric interphase approach targets the same sites by coating internal surfaces rather than only the outer particle perimeter. Evidence quality is highest for the neutron work because it is performed on working cells; the interphase and glass-electrolyte studies remain at the materials or half-cell stage, leaving open the question of how boundary coverage evolves under realistic stack pressure and electrode porosity.\nMaterials and interfaces Work on sulfide and oxide solid electrolytes continues to emphasize interfacial rather than bulk properties. The elastomeric coating and the in-situ glass electrolyte both aim to passivate grain boundaries and reduce contact resistance. In parallel, the gradient-solvation electrolyte modifies the liquid-side solvation sheath to limit reduction at the lithium surface. None of the reports quantify how these modifications alter the critical current density or the chemo-mechanical stress that develops when the cell is cycled at practical stack pressures.\nScale-up, safety and manufacturing Physical pressure is presented as a route to longer cycle life, yet the claim rests on a commercial narrative without accompanying data on cell format, pressure magnitude, or retention threshold. The sodium-sulfur glass-electrolyte pouch-cell result is closer to a manufacturing-relevant format, but the absence of reported stack pressure and critical current density leaves the safety margin unspecified. Redox-flow scale-up considerations appear in a separate Nature Energy column, underscoring that solid-state systems still lack equivalent cell-level manufacturing constraints.\nQuick Radar Neutron imaging shows lithium accumulation remains spatially heterogeneous even in cells with high bulk conductivity. Elastomeric interphase coverage inside cathode particles needs verification after repeated volume changes at electrode scale. Direct-growth Na solid glass electrolyte reduces interfacial resistance but critical current density data are missing. Gradient-solvation electrolyte stabilizes lithium metal; boundary-specific diagnostics are still required. ML models for ionic conductivity in solid electrolytes rely on compositional and structural features whose predictive power outside the training set is untested. Physics-informed degradation detection for recycling uses sparse pulse data; transferability across cell formats remains open. Closing The recurring observation is that boundary-specific transport and mechanics, not average material properties, determine whether a solid-state or high-voltage cell survives repeated cycling. What boundary diagnostic would you add to your next formation protocol to test this directly?\nSources EKL Batteries: In Situ-Constructed Elastomeric Interphase for Grain Boundary Stabilization in High-Voltage Layered Oxide Cathodes - https://advanced.onlinelibrary.wiley.com/doi/10.1002/adma.74129?af=R EKL Batteries: Direct Growth of Na-Ion Conducting Na3O15Si6Y Solid Glass Electrolyte With Reduced Interfacial Resistance for Safer Room-Temperature Sodium-Sulfur Pouch Cells - https://onlinelibrary.wiley.com/doi/10.1002/anie.6051760?af=R EKL Batteries: Machine Learning Prediction of Ionic Conductivity in Solid-State Electrolytes Using Compositional, Structural, and Neural Potential Features - https://chemrxiv.org/doi/abs/10.26434/chemrxiv.15005871/v1?af=R MIT News - Batteries: Discovery helps explain why solid-state batteries often fail - https://news.mit.edu/2026/discovery-helps-explain-why-solid-state-batteries-often-fail-0706 Tech Xplore - Energy \u0026amp; Green Tech: Neutrons track lithium in working solid-state battery, revealing uneven charging - https://techxplore.com/news/2026-07-neutrons-track-lithium-solid-state.html EKL Batteries: Electrolyte Dynamics in High-Ni NMC Observed via Operando Neutron Imaging - https://chemrxiv.org/doi/abs/10.26434/chemrxiv.15005849/v1?af=R Batteries News: Physical pressure could make EV batteries last twice as long and reduce environmental impact - https://batteriesnews.com/physical-pressure-could-make-ev-batteries-last-twice-as-long-and-reduce-environmental-impact/ Nature Portfolio - Batteries: Single-phase gradient-solvation-electrolyte-stabilized Li metal batteries - https://www.nature.com/articles/s41586-026-10732-z ","permalink":"https://interphasebrief.com/newsletter/2026-w29/","summary":"\u003cp\u003eGrain boundaries and solid-solid interfaces, rather than bulk conductivity, set the practical limits on dendrite formation, lithiation uniformity, and interphase stability in solid-state and high-voltage systems.\u003c/p\u003e\n\u003cp\u003eSolid-state electrolytes were expected to eliminate liquid-related safety risks while supporting higher energy density. In practice, lithium filaments still appear at internal boundaries where two grains of electrolyte meet. The MIT study isolates these grain boundaries as nucleation sites because they locally alter the electric field and provide fast diffusion paths that concentrate lithium. This shifts attention from electrode-electrolyte contact alone to the polycrystalline microstructure itself.\u003c/p\u003e","title":"Interphase Brief - Week 29, 2026"},{"content":"Grain-boundary charge and local mechanical stress now emerge as coupled controls on dendrite initiation and short-circuit endurance in garnet-type solid electrolytes.\nSolid-state batteries continue to show dendrite-driven failures even when bulk ionic conductivity meets targets. Recent work isolates the electrolyte grain boundaries themselves as the sites where lithium filaments first nucleate, rather than the electrode-electrolyte interface alone. The MIT study traces dendrite seeding to the two-grain junctions where local chemistry and transport differ from the grain interior. Two Nature papers add that these boundaries carry net charge and that applied biaxial stress alters the trajectory of any growing filament. Together the results shift attention from maximizing conductivity to controlling boundary potential and stress state during processing and cycling.\nThe practical question is whether existing densification routes already set the boundary charge and residual stress that later determine endurance. Ti substitution in LLZO is examined precisely for its effect on microstructure and grain-boundary density. Separate manufacturing routes, such as ultrasonic spray or 3D printing of polymer electrolytes, alter the same boundary population through different thermal and mechanical histories. Until boundary-specific measurements are routine, claims that a new solid electrolyte solves the dendrite problem remain incomplete.\nThe essentials Grain-boundary nucleation sites. The MIT report shows that lithium filaments originate at electrolyte grain boundaries rather than solely at the electrode interface. Post-mortem imaging links filament position to the two-grain junctions where local defect chemistry differs. The unresolved issue is whether the observed boundary chemistry is intrinsic or set by the sintering atmosphere and cooling rate.\nCharged boundaries and short-circuit limits. The Nature study on garnet electrolytes demonstrates that space-charge layers at grain boundaries reduce the critical current density for short-circuit. Impedance and electron microscopy map the boundary potential directly to endurance under constant-current hold. It remains unclear how the measured boundary charge changes once a cell is assembled under stack pressure.\nBiaxial stress and dendrite deflection. A second Nature paper reports that compressive biaxial stress deflects growing dendrites away from the through-plane direction. The deflection correlates with changes in the local stress field rather than with bulk modulus alone. The open question is whether the same stress state can be maintained across the full area of a large-format cell during formation and cycling.\nTi substitution and LLZO microstructure. The arXiv preprint examines Ti doping in Li7La3Zr2O12 to alter densification and grain size. Smaller grains increase boundary area while changing the cubic-phase fraction. The work does not yet report boundary-specific conductivity or critical-current data under applied pressure.\nDry electrode processing constraints. The PTFE-free graphite granule route avoids fluorinated binders yet must still achieve electronic percolation without introducing new pore networks that later concentrate current at solid-electrolyte boundaries. No cycling data under stack pressure are supplied, leaving the interaction between electrode tortuosity and boundary failure unquantified.\nMechanism and evidence The clearest mechanistic signal is that grain-boundary charge and local stress together set the site and direction of dendrite growth. The MIT imaging places filaments at two-grain junctions; the Nature boundary-potential measurements supply an electrostatic driving force; the stress-deflection results add a mechanical steering term. Evidence quality is high for the location and trajectory observations but remains indirect for the quantitative link between boundary charge density and critical current. No study yet reports operando boundary potential under simultaneous stack pressure and temperature, so the relative weight of electrostatic versus mechanical contributions is still unresolved.\nMaterials and interfaces Garnet LLZO remains the dominant platform. Ti doping is shown to modify grain size and phase purity, yet the effect on boundary space-charge layers is not measured. Polymer electrolytes deposited by ultrasonic spray or 3D printing create thinner films with controlled thickness, but the resulting interfaces with lithium or composite cathodes receive no post-cycling chemical analysis. Sodium-ion work on Prussian blue points to surface oxidation during dehydration as the dominant degradation path, separate from the solid-state lithium thread.\nScale-up, safety and manufacturing PTFE-free dry electrode processing removes one fluorinated component yet introduces new requirements for granule shape control to maintain electronic pathways. 3D-printed solid polymer electrolytes target wide-temperature operation through dielectric tuning, but the prints must still survive the same stack pressures that govern garnet endurance. No data address how residual solvent or curing gradients affect long-term interfacial contact. The absence of critical-current or short-circuit metrics under realistic pressure leaves the safety margin unspecified.\nQuick Radar MOF-glass hard-carbon study: Reports durable sodium storage but supplies no post-cycling interface spectra. Single-crystal Ni-rich cathode work: Tracks internal stress during phase transformation without specifying electrolyte or pressure conditions. Zwitterionic polymer electrolytes: Claim dipole-assisted conduction yet omit critical-current measurements. Li-air-inspired electrodialysis: Targets direct lithium carbonate recovery; purity under realistic brine compositions is not stated. Silicon synthesis via neutron-verified routes: Improves precursor control but does not address volume-expansion accommodation in full cells. Asymmetric flame-retardant gel electrolytes for sodium metal: Described without stack-pressure or temperature-window data. Closing The immediate experimental need is to measure grain-boundary potential and local stress simultaneously inside an operating solid-state cell so that processing routes can be judged by the failure mode they actually set.\nSources Nature Portfolio - Batteries: Charged grain boundaries limit short-circuit endurance in garnet solid-state battery electrolytes - https://www.nature.com/articles/s41565-026-02206-0 MIT News - Batteries: Discovery helps explain why solid-state batteries often fail - https://news.mit.edu/2026/discovery-helps-explain-why-solid-state-batteries-often-fail-0706 Nature Portfolio - Batteries: Dendrite initiation and deflection in biaxially stressed solid electrolytes - https://www.nature.com/articles/s41586-026-10734-x arXiv - Solid-state batteries query: Optimizing Ti substitution for the enhanced densification, ionic conductivity, and microstructure of garnet-type Li$_7$La$_3$Zr$2$O${12}$ solid electrolytes - https://arxiv.org/abs/2606.31669v1 EKL Batteries: 3D-Printed Ultra-Thin Solid Polymer Electrolytes with Superior Dielectric Properties for Wide Temperature Range All-Solid-State Batteries - https://advanced.onlinelibrary.wiley.com/doi/10.1002/adma.202523142?af=R Tech Xplore - Energy \u0026amp; Green Tech: PTFE-free dry battery electrode could speed EV charging and extend range - https://techxplore.com/news/2026-07-ptfe-free-dry-battery-electrode.html ","permalink":"https://interphasebrief.com/newsletter/2026-w28/","summary":"\u003cp\u003eGrain-boundary charge and local mechanical stress now emerge as coupled controls on dendrite initiation and short-circuit endurance in garnet-type solid electrolytes.\u003c/p\u003e\n\u003cp\u003eSolid-state batteries continue to show dendrite-driven failures even when bulk ionic conductivity meets targets. Recent work isolates the electrolyte grain boundaries themselves as the sites where lithium filaments first nucleate, rather than the electrode-electrolyte interface alone. The MIT study traces dendrite seeding to the two-grain junctions where local chemistry and transport differ from the grain interior. Two Nature papers add that these boundaries carry net charge and that applied biaxial stress alters the trajectory of any growing filament. Together the results shift attention from maximizing conductivity to controlling boundary potential and stress state during processing and cycling.\u003c/p\u003e","title":"Interphase Brief - Week 28, 2026"},{"content":"Interphase Brief is a weekly scientific brief on battery materials, electrochemical interfaces and energy-storage science.\nEvery Monday, it tracks the technical signals behind battery progress: solid-state electrolytes, interphases, degradation, lithium metal, sodium-ion systems, electrode processing, operando characterization, safety and scale-up.\nWhat is Interphase Brief Battery research moves fast. New papers, preprints, characterization methods, cell formats, electrolyte claims, degradation mechanisms and manufacturing routes appear every week, often with very different levels of evidence.\nInterphase Brief filters that stream. It monitors scientific and technical sources, identifies the most relevant signals, and turns them into a concise brief with context, caveats and mechanism-level interpretation.\nThe goal is simple: separate real scientific and engineering signal from battery hype.\nWhat you will find every Monday Opening note - A mechanism-focused take on the most relevant development of the week.\nThe five signals that matter - The most important papers, results and technical developments, explained with scientific context.\nInterphase and degradation watch - SEI, CEI, electrolyte decomposition, cathode-electrolyte reactions, dendrites, aging and failure localization.\nSolid-state and lithium metal - Garnets, sulfides, polymers, interfaces, pressure, grain boundaries and short-circuit mechanisms.\nSodium-ion and alternative chemistries - Hard carbon, Prussian blue analogues, electrolytes, electrode stability and scale-up constraints.\nManufacturing and scale-up - Dry electrodes, coating, calendering, recycling, precursor recovery, cell assembly and process-linked failure modes.\nCharacterization note - Operando methods, impedance, microscopy, spectroscopy, diffraction and what each method does or does not prove.\nEngineering takeaway - One concrete implication for researchers, engineers or technical decision-makers.\nRecommended reads - Papers, preprints, reviews and technical resources worth your time.\nHow Interphase Brief is made Interphase Brief is generated by an AI. Reviewed by another AI.\nEvery week, a fully automated system monitors relevant battery and electrochemistry sources, synthesizes what matters and publishes the result. A first AI drafts the brief; a second AI reviews it editorially. What you read is the direct output of that pipeline.\nWe disclose this openly because a scientific brief that uses AI should say so plainly. The point is not to imitate a traditional editorial desk. The point is to show how an automated research-monitoring system can produce useful, transparent and technically disciplined signal.\nEditorial philosophy Mechanism first. Performance numbers matter, but mechanisms explain whether a result is portable.\nSkeptical of hype. Breakthrough language is treated with caution. Evidence, methods and constraints matter more than claims.\nInterfaces matter. Many battery failures localize at boundaries, contacts, interphases and surfaces. The brief pays special attention to where failure starts.\nScale-up aware. Lab-scale evidence is not treated as commercial proof. Manufacturing, pressure, safety, reproducibility and cell-level validation are part of the story.\nPrimary sources first. Papers, preprints, technical reports and original source material take priority over secondary coverage.\nGlobal scope. Battery science is international. Sources, institutions and technical challenges come from everywhere.\nFree subscription Receive Interphase Brief every Monday in your inbox. No cost, no spam, no small print.\nSubscribe on Buttondown\nContact Suggestions, corrections or a source you think should be monitored?\nWrite to us at interphasebrief@proton.me or via X at @interphasebrief.\n","permalink":"https://interphasebrief.com/about/","summary":"\u003cp\u003e\u003cstrong\u003eInterphase Brief\u003c/strong\u003e is a weekly scientific brief on battery materials, electrochemical interfaces and energy-storage science.\u003c/p\u003e\n\u003cp\u003eEvery Monday, it tracks the technical signals behind battery progress: solid-state electrolytes, interphases, degradation, lithium metal, sodium-ion systems, electrode processing, operando characterization, safety and scale-up.\u003c/p\u003e\n\u003ch2 id=\"what-is-interphase-brief\"\u003eWhat is Interphase Brief\u003c/h2\u003e\n\u003cp\u003eBattery research moves fast. New papers, preprints, characterization methods, cell formats, electrolyte claims, degradation mechanisms and manufacturing routes appear every week, often with very different levels of evidence.\u003c/p\u003e","title":"About Interphase Brief"}]