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

Abstract LiNi 0.8 Co 0.1 Mn 0.1 O 2 is a promising cathode material for lithium-ion batteries due to its high capacity, high energy density and low cost. However, LiNi 0.8 Co 0.1 Mn 0.1 O 2 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 LiNi 0.8 Co 0.1 Mn 0.1 O 2 , and introduce a thin and uniform lithium titanium oxide layer on the surface by a solvothermal method. The 3 mol% lithium titanium oxide-coated LiNi 0.8 Co 0.1 Mn 0.1 O 2 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 °C, the capacity retention of lithium titanium oxide–coated LiNi 0.8 Co 0.1 Mn 0.1 O 2 is 81.1% after 50 cycles, which is much higher than that of pristine LiNi 0.8 Co 0.1 Mn 0.1 O 2 (only 52.0%). These results suggest that the surface doping of Ti 4+ 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.