Study on surface treatment and electrochemical properties of cobalt-free lithium manganese based cathode materials

• 1、School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006

Abstract：cobalt-free lithium-rich manganese-based layered cathode materials have attracted much attention as potential cathode materials for the next generation of lithium-ion batteries due to their high reversible capacity and low-cost advantages. However, problems such as low first-cycle Coulombic efficiency, poor rate performance, and capacity attenuation limit this type of cathode material\'s further development. In this work, a citric acid solution was used to treat the surface of Li1.2Ni0.2Mn0.6O2 cathode material. Physical characterization and electrochemical testing of the treated samples proved that a spinel surface was formed on the surface of the layered cathode material. The surface spinel phase not only provided 3D channels for Li-ion diffusion but also acted as a buffer layer between the cathode material surface and the electrolyte to improve the first-cycle coulomb efficiency and the cycle performance. The electrochemical test results showed that the first-cycle Coulombic efficiency of the modified Li1.2Ni0.2Mn0.6O2 was increased from 78.43 % to 92.42 %, and the reversible specific capacity was increased from 270 mAh g-1 to 292m Ah g-1. The rate performance and capacity retention under prolonged cycles were also significantly improved.

Keywords： Materials science Li-ion Battery Li-rich materials Cobalt-free cathodematerials first-cycle coulomb efficiency Rate performance