Inorganic-gel hybrid electrolyte and in-situ artificial interlayer: A void-free design for high-performance solid-state Li batteries

Abstract

Despite the extensive interest in solid-state lithium batteries (SSLBs), the voids/gaps inside the solid-state electrolyte (SSE) and between the SSE-electrode interfaces significantly limit the performance of the SSLBs. In this work, we developed a void-free design combining an inorganic-gel hybrid electrolyte with in-situ polymeric interlayers for SSLBs. The designed inorganic-gel hybrid SSE enables facile Li+ ion conduction, and the in-situ fabricated solid polymer electrolyte between the electrodes and the hybrid electrolyte improves interfacial compatibility. We found that, during the Li plating-stripping, the interfacial property between Li and SSE dictates critical current density, while bulk electrolyte properties affect cycling stability. Ascribed to its layered structure, our hybrid electrolyte efficiently mitigated dendritic Li deposition as revealed by a high specific capacity of 154 mAh g-1 at 0.3 C and extended cycling stability in LiFePO4-based SSLB. Moreover, in the solid-state Li-S batteries, the ionic liquid in the inorganic-gel hybrid electrolyte and the polymeric interlayer successfully regulates polysulfide dissolution at only cathode side and completely block its migration to the Li anode. The as-prepared solid-state Li-S cells delivers a high specific capacity of 845.6 mAh g-1 at 0.2 C with 81.2% capacity retention and a high Coulombic efficiency of 95.7% after 100 cycles under room temperature. Our void-free design for SSLBs could widen SSE compatibility in different Li+ ion-based battery systems.