Physics / mechanism
Solid-state batteries (SSBs) replace liquid/gel electrolyte with a solid ionic conductor — ceramic (oxide: LLZO, NASICON; sulfide: LGPS, argyrodite), polymer, or halide. Li⁺ transport occurs through lattice defects and grain boundaries rather than solvation shells. Key figures of merit: ionic conductivity (sulfides reach ~10⁻² S/cm at RT, approaching liquid electrolyte ~10⁻² S/cm), electrochemical stability window, interfacial resistance (typically 10–1000 Ω·cm² — the dominant unsolved problem), and critical current density before Li dendrite penetration. Energy density targets: >400 Wh/kg at cell level. State of art: Toyota, QuantumScape, Solid Power in late-stage prototype; sulfide systems lead on conductivity, oxides on stability.
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- To be added.