Surface-Modified Graphite Anodes for High-Rate Long-Cycling in Sulfide All-Solid-State Batteries

Graphite is a promising anode for realizing high power density in sulfide-based all-solid-state lithium batteries (ASSLIBs). However, their fast-charging capabilities are limited in practice. This paper demonstrates that the reactivity between lithiated graphite and sulfide electrolytes and undesirable side reactions at the amorphous carbon interface negatively affect the fast-charging capacities of ASSLIBs. On this basis, a lithium niobate-coated spherized natural graphite composite (LNO@SNG) synthesized via a scalable sol-gel method was employed to form an electrochemically stable interface with Li₆PS₅Cl electrolyte. Full cells assembled with a LiNi_0.7Co_0.2Mn_0.1O₂ cathode and LNO@SNG anode demonstrated cycling stability under low stack pressures (≤5 MPa), at high rates (up to 12C), and even with high cathode loading (30.57 mg·cm^-2), respectively, and achieved a capacity retention of 96.5% after 600 cycles at 4 mA·cm^-2 (6C). The surface-modified graphite anode combines cost effectiveness, interfacial stability, and superior rate capability, promising to be a major boost for ASSLIB commercialization.