Systematic study of the effects of lithium deficiencies on the crystal structure and electrochemical performance of Li-rich materials

A series of Li-rich materials with lithium deficiencies are obtained by a mild sol-gel and high-temperature calcination method. We use conventional test methods, such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy, to analyze the crystal structure and morphology of as-prepared materials. The results show that the Li1.1Mn0.54Co0.13Ni0.13O2 (named L1.1) displays superior electrochemical performance, that is, the discharge capacities are 303.9 and 145 mAh g−1 at rate of 0.1 C and 5 C, respectively. The excellent rate capability is mainly attributed to the formation of lithium vacancy and the formation of distorted lattice fringes, which enlarged the Li slab and changed the local structures in the L1.1 material.