Chemo-Mechanical Interphase Stabilization of Silicon-Based Anodes for High-Energy All-Solid-State Batteries

Abstract Silicon anodes show great potential for high-energy-density all-solid-state lithium batteries, but their substantial volume changes during cycling result in the loss of solid-solid contact, while parasitic interfacial reactions generate significant interfacial resistance. Herein, we present a chemo-mechanical stabilization strategy using a high-capacity, carbon-free silicon suboxide (SiOx) anode. The in situ formation of a Li2O/LixSiOy-rich matrix maintains continuous ion-transport pathways by stabilizing interfacial contact and mitigates parasitic reactions with sulfide electrolytes. As a result, the SiOx anode operates at current densities up to 5.0 mA cm−2 and delivers an areal capacity of 2.3 mA h cm−2. Furthermore, full cells achieve 70.3% capacity retention after 400 cycles at 1.0 mA cm−2, with a reversible areal capacity of 1.6 mA h cm−2. Moreover, a molten-salt-enabled surface coating was employed, which improved the electronic conductivity of SiOx by two orders of magnitude. This work offers a new avenue toward high-energy ASSLBs based on SiOx anodes.