Stable Molten Salts Mediated Growth of Single-Crystalline LiNi0.8Co0.1Mn0.1O2 with High Voltage Tolerance

Abstract

As electronic devices rapidly iterate and power batteries continuously upgrade, the demand for cathode materials with high energy density is becoming increasingly stringent. This trend not only drives the development of high voltage cathode materials, but also imposes great challenges on their repair and regeneration toward enhanced battery performance. This study presents a stable eutectic molten salt approach, utilizing an optimized KCl-LiCl-LiOH system that effectively mitigates lithium volatilization at the elevated temperatures. Moreover, this system enables sufficient single-crystal reconstruction of fractured polycrystalline cathodes, achieving high structural stability and voltage tolerance in the regenerated cathode without further modification. The regenerated cathode (R-NCM) exhibits superior structural and electrochemical stability, retaining 81.7% of its capacity after 400 cycles at 1 C with a cutoff voltage of 4.5 V, compared to 51.5% capacity retention for commercial cathodes (C-NCM) under the same conditions. Even under high-rate cycling conditions at 5 C, R-NCM still retains 88.3% of its capacity after 200 cycles. The findings highlight the potential of direct regeneration methods to fulfill the growing demand for high-performance high voltage cathodes.