Dry Pre‐Lithiation for Graphite‐Silicon Diffusion‐Dependent Electrode for All‐Solid‐State Battery

Abstract The graphite/silicon‐based diffusion‐dependent electrodes (DDEs) are one of the promising electrode designs to realize high energy density for all‐solid‐state batteries (ASSBs) beyond conventional composite electrode design. However, the graphite/silicon‐based electrode also suffers from large initial irreversible capacity loss and capacity fade caused by significant volume change during cycling, which offsets the advantages of the DDEs in ful‐cell configuration. Herein, a new concept is presented for DDEs, dry pre‐lithiated DDEs (PL‐DDEs) by introducing Li metal powder. Since Li metal powder provides Li ions to graphite and silicon even in a dry state, the lithiation states of active materials is increased. Moreover, the residual Li within PL‐DDE further serves as an activator and a reservoir for promoting the lithiation reaction of the active materials and compensating for the active Li loss upon cycling, respectively. Based on these merits, ASSBs with PL‐DDE exhibit excellent cycling performance with higher columbic efficiency (85.2% retention with 99.6% CE at the 200th cycle) compared to bare DDE. Therefore, this dry lithiation process must be a simple but effective design concept for DDEs for high‐energy‐density ASSBs.