Synthesis and electrochemical properties of Co,Mn-coated LiNiO2 lithium-ion battery cathode materials

Effect of a Co,Mn coating on the structure and electrochemical properties of the LiNiO2 cathode material was investigated using XRD, TEM, XPS, cyclic voltammetry and EIS. Co,Mn coating formed not only a thin layer but a solid solution by interacting with core material on the surface LiNiO2 cathode particles. Co,Mn-coated LiNiO2 behaved much better, losing about 8.9% of its initial capacity (181.3 mAh g−1) after 50 cycles at 150 mAg−1. While the uncoated LiNiO2 lost about 26.9% of its initial capacity (183.3 mAh g−1). Based on these results from composition analysis and electrochemical tests, it was found that the coating layer consisted of Co,Mn particles attached to the particle surface and the Co,Mn layer significantly improved the electrochemical properties of the cathode by not only suppressing the phase transition but also decreasing the impedance growth at the interface between the electrodes and the electrolyte during charge–discharge cycling.