Reduced Lithium/Nickel Disorder Degree of Sodium-Doped Lithium-Rich Layered Oxides for Cathode Materials: Experiments and Calculations

Abstract

Sluggish kinetics and poor electrochemical stability limit the implications of Li-rich layered oxide cathode materials, which are regarded as one of the most promising potential cathode materials for lithium-ion batteries. In this work, a Na-doped Li-rich layered oxide (abbreviated as N-LLO) cathode material is prepared through co-precipitation combined with calcination. During the annealing process, partial Li2CO3 is substituted by Na2CO3, which helps to optimize the primary particles and realize Na doping. The obtained N-LLO cathode exhibits a greater specific capacity and excellent rate performance. The characterization and DFT calculations suggest that the doped Na ions could reduce the formation of Li/Ni disorder defects, change local bond length, and enlarge Li interslab spacing conducive to Li-ion diffusion, improving the rate performance.