Single crystal cathodes enabling high-performance all-solid-state lithium-ion batteries

All-solid-state lithium-ion batteries (ASSLIBs) are receiving significant attention owing to their improved safety and energy density over liquid counterparts. However, single-crystal cathodes have never been investigated in ASSLIBs. In this work, single-crystal Li(Ni0·5Mn0·3Co0.2)O2 (SC-NMC532) is used as the cathode material for ASSLIBs, which exhibits 6–14 times higher Li+ diffusion coefficient than polycrystalline Li(Ni0·5Mn0·3Co0.2)O2 (PC-NMC532). As a result, SC-NMC532 exhibits an initial specific capacity of 156.4 ​mAh.g−1 while PC-NMC532 shows an initial capacity of only 127.5 ​mAh.g−1. After 150 cycles, SC-NMC532 retains the capacity of 94.5 ​mAh.g−1. More impressively, under a high current density of 1.3 ​mA ​cm−2, SC-NMC532 exhibits a capacity of 82 ​mAh.g−1, much higher than that of PC-NMC532 (2.1 ​mAh.g−1). This work demonstrates that single-crystal NMC cathodes could enable both high power density and high energy density of ASSLIBs.