Bulk/Interfacial Structure\nDesign of Li-Rich Mn-Based\nCathodes for All-Solid-State Lithium Batteries

Li-rich Mn-based cathode materials (LRMO) are promising\nfor enhancing\nenergy density of all-solid-state batteries (ASSBs). Nonetheless,\nthe development of efficient Li<sup>+</sup>/e<sup>–</sup> pathways\nis hindered by the poor electrical conductivity of LRMO cathodes and\ntheir incompatible interfaces with solid electrolytes (SEs). Herein,\nwe propose a strategy of <i>in</i>-<i>situ</i> bulk/interfacial structure design to construct fast and stable Li<sup>+</sup>/e<sup>–</sup> pathways by introducing Li<sub>2</sub>WO<sub>4</sub>, which reduces the energy barrier for Li<sup>+</sup> migration and enhances the stability of the surface oxygen structure.\nThe reversibility of oxygen redox was improved, and the voltage decay\nof the LRMO cathode was addressed significantly. As a result, the\nbulk structure of the LRMO cathodes and the high-voltage solid–solid\ninterfacial stability are improved. Therefore, the ASSBs achieve a\nhigh areal capacity (∼3.15 mAh/cm<sup>2</sup>) and outstanding\ncycle stability of ≥1200 cycles with 84.1% capacity retention\nat 1 C at 25 °C. This study offers new insights into LRMO cathode\ndesign strategies for ASSBs, focusing on ultrastable high-voltage\ninterfaces and high-loading composite electrodes.