Enhanced rate and high-temperature performance of La0.7Sr0.3MnO3-coated LiNi0.5Mn1.5O4 cathode materials for lithium ion battery

Abstract La 0.7 Sr 0.3 MnO 3 -coated 5 V spinel LiNi 0.5 Mn 1.5 O 4 as cathode is prepared by mixing LiNi 0.5 Mn 1.5 O 4 powders and the sol–gel-drived La 0.7 Sr 0.3 MnO 3 matrix, followed by high-temperature calcinations. The effect of La 0.7 Sr 0.3 MnO 3 -coating on the electrochemical performances of LiNi 0.5 Mn 1.5 O 4 cells, especially at elevated temperature, is investigated systematically by the charge/discharge testing, cyclic voltammograms and AC impedance spectroscopy, respectively. Compared to pristine LiNi 0.5 Mn 1.5 O 4 , La 0.7 Sr 0.3 MnO 3 -coated material has much lower surface and charge-transfer resistances and shows a higher lithium diffusion rate. The results of electrochemical experiments demonstrate that the modified material exhibits remarkably enhanced electrochemical reversibility and stability at elevated temperature. The La 0.7 Sr 0.3 MnO 3 -coating layer protected the surface of the active materials from HF in the electrolyte during electrochemical cycling. As a result, the electrochemical cycling stability is improved.