Maintaining Interfacial Transports for Sulfide-Based All-Solid-State Batteries Operating at Low External Pressure

Abstract

All-solid-state batteries (ASSBs) have attracted considerable attention due to their theoretically high energy density and safety. However, maintaining intimate interfacial contact at low external pressures remains a challenge, limiting large-scale practical applications. Here, a bottom-up design of all-solid-state electrodes is proposed by minimizing internal stress variation to maintain interfacial transport at low external pressures. Theoretical calculations and synchrotron X-ray techniques reveal that the surface-to-bulk pillar effect alleviates the volumetric strain of the cathode materials at high delithiation, which is favorable for improving the interfacial mechanical and chemical compatibility to create fast ion percolation networks of the electrode. Therefore, the 4.4 V sulfide-based ASSBs retain a high specific capacity (166.7 mAh g–1, 0.2C), good rate performance, and stable cyclability (90.8% retention) at the operating pressure of 2 MPa. This work sheds light on the design concept of electrochemomechanical manipulation, serving as a guideline for developing practically acceptable low-pressure ASSBs.