A new sintering mechanism, “silver-zipping”, for low-temperature sintering of oxide solid electrolytes

Oxide-based solid electrolytes promise safe, high energy density all-solid-state batteries (ASSBs), but require high sintering temperature, which impairs cathode-electrolyte compatibility and manufacturability. Incorporating Ag nanoparticles enables low-temperature densification of a γ-Li ₃ PO ₄ -type LISICON (Li _3.5 Ge _0.4 Si _0.1 V _0.4 O ₄ ) via a ‘silver-zipping’ mechanism that transiently hosts Li, reduces local coulomb repulsion between solid electrolyte particles, and accelerates neck growth. The resulting microstructure yields higher ionic conductivity without a measurable rise in electronic conductivity, serves as both separator and catholyte, and co-processes with layered oxides at ≤ 750°C without parasitic phases. The strategy provides a practical route to low-temperature processing of oxide-based ASSBs with improved interfacial compatibility and manufacturability.