High Energy Sulfide-Based All-Solid-State Lithium\nBatteries Enabled by Single-Crystal Li-Rich Cathodes

High-capacity\nLi-rich Mn-based oxides (LRMOs) show great potential\nfor enhancing the energy density of all-solid-state lithium batteries\n(ASSLBs). However, the intrinsically low electronic/ionic conductivity\nof LRMOs and bulk structural degradation lead to an inferior electrochemical\nperformance. Herein, a single-crystal Li<sub>1.2</sub>Ni<sub>0.13</sub>Mn<sub>0.54</sub>Co<sub>0.13</sub>O<sub>2</sub> (SC- LRMO) cathode\nis developed to address the challenges associated with charge-transport\nlimitations and mechanical degradation of conventional polycrystalline\n(PC)-LRMO in ASSLBs. The results indicate that composite cathodes\nusing small SC-LRMO achieve excellent electrochemical performance.\nSpecifically, SC-LRMO not only delivers a high specific capacity of\n316 mAh g<sup>–1</sup> at 0.05C but also exhibits a capacity\nretention of 86% after 300 cycles at 1C, outperforming the PC-LRMO\n(243 mAh g<sup>–1</sup>, 84%). Comprehensive characterization\nreveals that the small single-crystal microstructure of SC-LRMO facilitates\nelectrochemical reaction and mitigates detrimental mechanical degradation.\nOverall, this work expedites the practical application of LRMO cathodes\nin high-energy-density ASSLBs through dedicated morphology design.