Interfacial-Oxygen-Regulated Lithium-Rich Manganese-Based Cathode for High-Performance Solid-State Lithium Batteries

High-capacity lithium-rich manganese-based materials Li_1.20Mn_0.54Ni_0.13Co_0.13O₂ (LRMs) are potential cathodes for solid-state lithium batteries with high energy density. However, there are challenges of low initial Coulomb efficiency (ICE) and interfacial degradation of the cathode caused by irreversible oxygen release. Here, the oxygen-deficient ceria (CeO_2-<i>x</i>) with abundant oxygen vacancies was used to scavenge excess oxygen species and manipulate the irreversible oxygen evolution of the LRM cathode in the solid-state lithium battery. CeO_2-<i>x</i> realizes the reversible storage and release of anion oxygen by the oxygen vacancies, and the doping of Ce^3+/4+ into the lattice stabilizes the structure and enhances the Li⁺ transport kinetics. Therefore, the cell with a NASICON-type F-doped Li_1.3Al_0.3Ti_1.7(PO_3.93F_0.07)₃ (F-LATP) solid electrolyte and LRM cathode shows a high ICE of 86.74%, an outstanding rate performance of 70.0 mAh g^-1 at 1 C, and a remarkable cyclability with a lower capacity decay rate of 0.27% per cycle. It is believed that this work provides valuable guidance for the design of reversible oxygen redox in high-capacity LRMs for solid-state batteries.