Synthesis and properties of single-crystal Ni-rich cathode materials in Li-ion batteries
Shijie Lu, Yang Liu, Zhenjiang He, Yunjiao Li, Junchao Zheng, Jing Mao, Kehua Dai
Abstract
Single-crystal Ni-rich cathode material LiNi0.88Co0.09Al0.03O2 (SC) was synthesized by a high-temperature solid-state calcination method. Physicochemical properties of primary and delithiated SC samples were investigated by X-ray diffractometry, X-ray photoelectron spectroscopy, and transmission electron microscopy. Electrochemical performance was characterized by long-term cycling, cyclic voltammetry, and in-situ impedance spectroscopy. The results indicated that high temperature rendered layered oxides to lose lithium/oxygen in the interior and exterior, and induced cationic disordering. Besides, the solid-phase synthesis process promoted phase transformation for electrode materials, causing the coexisting multi-phase in a single particle. High temperature can foster the growth of single particles, but it caused unstable structure of layered phase.