Boosting Anionic Redox Reactions of Li-Rich Cathodes through Lattice Oxygen and Li-Ion Kinetics Modulation in Working All-Solid-State Batteries

The use of lithium-rich manganese-based oxides (LRMOs) as the cathode in all-solid-state batteries (ASSBs) holds great potential for realizing high energy density over 600 Wh kg⁻¹. However, their implementation is significantly hindered by the sluggish kinetics and inferior reversibility of anionic redox reactions of oxygen in ASSBs. In this contribution, boron ions (B³⁺) doping and 3D Li₂B₄O₇ (LBO) ionic networks construction are synchronously introduced into LRMO materials (LBO-LRMO) by mechanochemical and subsequent thermally driven diffusion method. Owing to the high binding energy of B─O and high-efficiency ionic networks of nanoscale LBO complex in cathode materials, the as-prepared LBO-LRMO displays highly reversible and activated anionic redox reactions in ASSBs. The designed LBO-LRMO interwoven structure enables robust phase and LBO-LRMO|solid electrolyte interface stability during cycling (over 80% capacity retention after 2000 cycles at 1.0 C with a voltage range of 2.2–4.7 V vs Li/Li⁺). This contribution affords a fundamental understanding of the anionic redox reactions for LRMO in ASSBs and offers an effective strategy to realize highly activated and reversible oxygen redox reactions in LRMO-based ASSBs.