Surface-modified Li[Li0.2Mn0.54Ni0.13Co0.13]O2 nanoparticles with LaF3 as cathode for Li-ion battery

The LaF3-coated Li[Li0.2Mn0.54Ni0.13Co0.13]O-2 nanoparticles were synthesized via co-precipitation method followed by simple chemical deposition process. The crystal structure, particle morphology, and electrochemical properties of the bare and coated materials were studied by XRD, SEM, TEM, charge-discharge tests. The results showed that the surface coating on Li[Li0.2Mn0.54Ni0.13Co0.13]O-2 nanoparticles were amorphous LaF3 layer with a thickness of about 10-30 nm. After the surface modification with LaF3 films, the coating layer served as a protective layer to suppress the side reaction between the positive electrode and electrolyte, and the Li[Li0.2Mn0.54Ni0.13Co0.13]O-2 oxide demonstrated the improved electrochemical properties. The LaF3-coated Li[Li0.2Mn0.54Ni0.13Co0.13]O-2 electrode delivered the capacities of 270.5, 247.9, 197.1, 170.0, 142.7, and 109.5 mAh g(-1) at current rates of 0.1, 0.2, 0.5, 1, 2, and 5 C rate, respectively. Besides, the capacity retention was increased from 85.1 to 94.8 % after 100 cycles at 0.5 C rate. It implied surface modification with LaF3 played an important role to improve the cyclic stability and rate capacity of the Li-rich nickel manganese oxides.