Enhancing the elevated temperature performance of high voltage LiNi_0.5Mn_1.5O₄ by v doping with in-situ carbon and polyimide encapsulation

We report the enhanced electrochemical performance of high voltage LiNi_0.5Mn_1.5O₄ cathode by small amount of aliovalent doping in Li-site (Li_0.995V_0.005Ni_0.5Mn_1.5O₄) and polyimide-carbon (PI-C) coating as well. Such small amount of V-doping in Li-sites leads to the crystallization of ordered spinel. The performances of the cathodes are studied in half-cell assembly at elevated temperature conditions (50, 55 and 60°C). Although, the notable improvement in elevated temperature conditions are noted for Li_0.995V_0.005Ni_0.5Mn_1.5O₄ phase at 50°C, but not sustained while increasing to 55 and 60°C. Nevertheless, the combined advantages of mixed conducting (ionic and electronic) features of PI-C, an excellent performance are noted for the Li_0.995V_0.005Ni_0.5Mn_1.5O₄ phase after introducing the PI-C layer, irrespective of the testing temperature. Cyclic voltammetry and impedance studies are also performed to corroborate the Li-ion kinetics.