Stabilizing reaction interface in Ni-rich layered oxides cathode for high-performance lithium-ion batteries at a high cutoff voltage

Nickel-rich layered oxide materials have been considered as promising cathodes for Li-ion batteries (LIBs) due to their high electrochemical capacities and low costs. However, the capacity fading and voltage decay during the cycle at high voltage hinders its practical application, resulting from the surface instability and bulk structural transformation. Here, we constructed a high-voltage-stable interface of Lin(TM)mPO4 (LTMPO, TM = Ni, Co, and Mn) by surface treatment to improve the voltage and capacity stability of LiNi0.8Co0.1Mn0.1O2 (NCM811) during cycling. The formed LTMPO nanolayer with better ionic conductivity and bonds with the surface of host NCM811 by a TM-O-P bond. As a result, the formed LTMPO interface could suppress the occurrence of surface side reactions and oxygen evolution, thus stabilizing the host structure and surface structure. The surface-modified NHP-2 electrode shows excellent capacity retention of 80.36% over 300 cycles at a high cut-off voltage of 4.5 V. This structure design strategy can effectively improve the electrochemical performance of NCM811 cathodes and promote the rapid development of high energy density Li-ion batteries (LIBs).