Enhanced cycle performance and synthesis of LiNi0.6Co0.2Mn0.2O2 single-crystal through the assist of Bi ion

Abstract

LiNi0.6Co0.2Mn0.2O2 (NCM622) single-crystal material was successfully prepared by introducing Bi ions. The influence of Bi ions introduction on the morphology, structure, and performance of NCM622 single-crystal material was explored. Introducing Bi ions can promote the growth of the primary particles of the cathode, and the NCM622 single-crystal material can be synthesized at a lower temperature. The single-crystal synthesized with the help of Bi ions can improve the interfacial stability of the material surface. And at a rate of 1C and voltage range of 2.8–4.3 V, the sample with 4000 ppm Bi addition introduced has a cycle retention rate of 88.67 % after 150 cycles. Simultaneously, we used SEM, XRD, EDS, TEM, XPS, and EBSD to reveal how Bi ions promote the generation of single-crystal morphology of cathode.