Synthesis of high-performance single-crystal LiNi0.8Co0.1Mn0.1O2 cathode materials by controlling solution super-saturation

Abstract

Layered LiNi0.8Co0.1Mn0.1O2 is a promising cathode material for use in lithium-ion batteries with high specific capacity. However, its electrochemical performance is limited by poor particle compaction density, fragmentation of secondary spherical particles, and serious cation mixing. These problems can be solved by the single-crystallization of particles. Accordingly, this paper proposes a novel method of synthesizing single-crystal cathode materials by controlling the solution super-saturation. The effects of changing the solution super-saturation on the microscopic morphology, structure, and electrochemical performance of single-crystal LiNi0.8Co0.1Mn0.1O2 materials are systematically investigated. A single-crystal cathode material prepared by adjusting the pH at 11.5 → 10.5 exhibits superior cycling and rate performance at 2.7–4.3 V compared with a material prepared at a fixed pH of 11.5. According to comprehensive test analyses, the single-crystal cathode material prepared by lowering the pH has a uniform size and good dispersibility, which shortens the transmission distance of Li+ from the electrolyte to the layered structure. It also reduces the degree of Li+/Ni2+ cation mixing in the material, which can effectively improve the Li+ transport efficiency. This study provides a novel pathway for the further improvement of energy density and cycling stability in high-nickel ternary cathode materials.