High-areal-capacity and long-life sulfide-based all-solid-state lithium battery achieved by regulating surface-to-bulk oxygen activity

Sulfide-based all-solid-state lithium batteries (ASSLBs) with nickel-rich oxide cathodes are emerging as primary contenders for the next generation rechargeable batteries, owing to their superior safety and energy density. However, the all-solid-state batteries with nickel-rich oxide cathodes suffer from performance degradation due to the reactions between the highly reactive surface oxygen of the cathode and the electrolyte, as well as the instability of the bulk oxygen structure in the cathode. Herein, we propose a synergistic modification design scheme to adjust the oxygen activity from surface to bulk. The LiBO₂ coating inhibits the reactivity of surface lattice oxygen ions. Meanwhile, Zr doping in the bulk phase forms strong Zr–O covalent bonds that stabilize the bulk lattice oxygen structure. The synergistic effect of these modifications prevents the release of oxygen, thus avoiding the degradation of the cathode/SE interface. Additionally, the regulation of surface-to-bulk oxygen activity establishes a highly stable interface, thereby enhancing the lithium ion diffusion kinetics and mechanical stability of the cathode. Consequently, cathodes modified with this synergistic strategy exhibit outstanding performance in sulfide-based ASSLBs, including an ultra-long cycle life of 100,000 cycles, ultra-high rate capability at 45C, and 85% high active material content in the composite cathode. Additionally, ASSLB exhibits stable cycling under high loading conditions of 82.82 mg cm⁻², achieving an areal capacity of 17.90 mA h cm⁻². These encouraging results pave the way for practical applications of ASSLBs in fast charging, long cycle life, and high energy density in the future.