Single-crystal Ni-rich layered oxide cathodes with LiNbO3-Li3BO3 coating for sulfide all-solid-state batteries

Sulfide all-solid-state batteries (SASSBs) with ultrahigh-nickel layered oxide cathode (LiNixCoyMn1-x-yO2, NCM, x >= 0.9) offer the potential of high energy density and safety for superior energy storage systems. However, stable cycling is difficult to realize due to adverse interfacial reactions, space charge layer (SCL), and elemental diffusion. Herein, we use a LiNbO3-Li3BO3 mixed coating of LiNbO3-Li3BO3 on a single-crystal Li[Ni0.92Co0.06Mn0.02]O2 (SC-Ni92) to enhance interfacial stability between SC-Ni92 cathode and sulfide solid electrolyte. Electrochemical performance shows that SC-Ni92@LiNbO3-Li3BO3/Li6PS5Cl/Li-In SASSBs exhibit the best electrochemical performance, including 88.4 % capacity retention at 1.50 mA cm-2 current density (1 C) for 100 cycles, and a discharge capacity of 150.1 mAh g-1 at 7.49 mA cm-2 high current density (5 C). The strategies adopted in this study provide valuable insights and guideline for the design of high-energy-density Ni-rich cathode materials for SASSBs.