In situ formed Li5AlO4-coated LiNi0.8Co0.1Mn0.1O2 cathode material assisted by hydrocarbonate with improved electrochemical performance for lithium-ion batteries

Abstract LiNi0.8Co0.1Mn0.1O2 has become a promising candidate as a cathode material of lithium ion batteries (LIBs) because of their high specific capacity, while the poor cycling and rate performances limit its commercial application. Herein, a thin layer of Li5AlO4 was in situ formed on the surface of LiNi0.8Co0.1Mn0.1O2 through a slow deposition process assisted by NaHCO3 and solid phase co-lithiation sintering. By employing the optimal amount (3 wt %) of Li5AlO4 coating on LiNi0.8Co0.1Mn0.1O2 cathode material (denoted as 3-NCM), the capacity retention rate of 3-NCM after 100 cycles increased from 75.06% to 89.15% at 2.8-4.3 V, and it also shows the most significantly enhanced rate performance. The outstanding electrochemical performance can be attributed to that the Li5AlO4 coating can impede the contact between the active materials and electrolyte, stabilize the material structure and inhibit the dissolution of transition metals during repeated charge–discharge cycles. And the superior conductivity of Li5AlO4 can improve the lithium ion diffusion rate. All these results connote that Li5AlO4-coated LiNi0.8Co0.1Mn0.1O2 cathode material might be employed in advanced lithium-ion batteries.