Surface coating with Li-Ti-O to improve the electrochemical performance of Ni-rich cathode material

LiNi0.8Co0.1Mn0.1O2 is a promising cathode material for lithium-ion batteries due to its high capacity, high energy density and low cost. However, LiNi0.8Co0.1Mn0.1O2 suffers from an aggressive side reaction with electrolyte, resulting in poor cycling performance, large polarization and fast voltage degradation. To overcome these drawbacks, we use an acid coprecipitation method to prepare rod-shaped LiNi0.8Co0.1Mn0.1O2, and introduce a thin and uniform lithium titanium oxide layer on the surface by a solvothermal method. The 3 mol% lithium titanium oxide-coated LiNi0.8Co0.1Mn0.1O2 exhibits a much higher capacity retention (88.6%) than the pristine material after 100 cycles, and the polarization and voltage degradation of the Ni-rich cathode are largely alleviated. Furthermore, at an elevated temperature of 65 degrees C, the capacity retention of lithium titanium oxide-coated LiNi0.8Co0.1Mn0.1O2 is 81.1% after 50 cycles, which is much higher than that of pristine LiNi0.8Co0.1Mn0.1O2 (only 52.0%). These results suggest that the surface doping of Ti4+ and the introduction of the lithium titanium oxide layer help to improve the structure stability and mitigate the side reactions on the electrode-electrolyte interface, resulting in good electrochemical performance.