Topic: Microstructure and Interface Stability in Solid-State Energy Storage Materials

The transition toward sustainable energy systems demands electrochemical storage technologies that combine high energy density, long-term reliability, and intrinsic safety. Solid-state batteries, leveraging inorganic or polymer-based solid electrolytes in place of flammable liquid counterparts, represent one of the most compelling pathways to meet these demands. Yet despite substantial progress, the practical realization of solid-state energy storage remains constrained by two deeply intertwined challenges: the design of functional microstructures and the stabilization of complex interfaces.

Interfaces in solid-state systems are not merely geometric boundaries — they are the sites where ionic transport is regulated, electrochemical reactions occur, mechanical stresses concentrate, and degradation initiates. In this sense, interface stability is itself a microstructural problem, one that spans length scales from the atomistic (interfacial bonding, space-charge layers, amorphization) to the mesoscale (grain boundary networks, polymer chain conformation, composite phase connectivity) and ultimately to macroscopic mechanical integrity under cycling. A microstructure-centered perspective — integrating atomistic interfacial chemistry, mesoscale transport pathways, and macroscale chemo-mechanical response — therefore offers a unifying framework for understanding and overcoming the core limitations of solid-state energy storage.

This Special Topic invites contributions that advance the understanding and control of microstructure and interfaces in solid-state energy storage materials, with an emphasis on mechanistic insight and multi-scale analysis. Topics of interest include, but are not limited to:

● Microstructure–property relationships in solid electrolytes— including halide, sulfide, oxide, oxyhalide, polymer, and composite electrolyte systems, with attention to how grain structure, polymer chain conformation and segmental dynamics, defect chemistry, filler–matrix interactions, and local ordering collectively govern ionic conductivity and mechanical compliance;

● Interface stability in solid-state batteries— electrochemical, chemical, and mechanical stability at electrode–electrolyte interfaces; interphase formation and evolution across inorganic, polymer, and composite electrolyte systems;

● In situ and operando characterization of microstructural evolution— cryo-TEM, synchrotron X-ray CT, operando XRD/PDF, and related techniques that reveal dynamic structural changes under realistic operating conditions;

● Multiphase and composite electrolyte/electrode systems— phase distribution, percolation, filler–polymer interactions, and ion transport in heterogeneous architectures;

● Chemo-mechanical coupling and mechanical degradation— stress generation, crack propagation, contact loss, and their microstructural origins in both inorganic and polymer-based systems;

● Computational modeling and data-driven approaches— DFT, MD, phase-field, and machine learning methods for microstructure and interface prediction and design across material classes.

Solid-state batteries, solid electrolytes, polymer electrolytes, composite electrolytes, microstructure, interface stability, interfacial engineering, chemo-mechanical coupling, in situ characterization, ionic transport, energy storage materials