Electrostatic interaction-driven inorganic coating layer toward improving battery performance for 5 V class high-voltage cathode in secondary batteries

One of the most promising high voltage cathode materials for application in lithium ion batteries (LIBs), the 5 V spinel LiNi0.5Mn1.5O4, faces electrode/electrolyte decomposition at high voltage, rendering commercial application difficult. To overcome these obstacles, this study proposes a method for adsorbing vanadium anion complexes on the surface of Ni0.25Mn0.75(OH)2 using cationic polymers and calcination them with LiOH to form LiNi0.5Mn1.5O4 with a uniform nano-Li3VO4 coating layer. The uniform nano-Li3VO4 coating layer prepared by the above method promotes transfer of lithium ions and protects active material from electrolyte corrosion, thereby obtaining a particularly stable electrochemical performance under severe operating conditions such as high temperatures. Electrochemical tests show that the Li3VO4-coated LiNi0.5Mn1.5O4 demonstrates a high discharge capacity and at the cycling test after storage test at 60 °C, the Li3VO4-coated LiNi0.5Mn1.5O4 shows higher capacity retention than pristine LiNi0.5Mn1.5O4; this can be attributed to the coating that acts as a protective layer.