Enhancing the elevated temperature performance of high voltage LiNi0.5Mn1.5O4 by V doping with in-situ carbon and polyimide encapsulation

• V-doped LiNi0.5Mn1.5O4 is prepared by scalable sol–gel technique.
• Li0.995V0.005Ni0.5Mn1.5O4 has been modified with dual layer i.e. polyimide-carbon.
• Excellent elevated temperature performances are noted at 50, 55 and 60 °C.

We report the enhanced electrochemical performance of high voltage LiNi0.5Mn1.5O4 cathode by small amount of aliovalent doping in Li-site (Li0.995V0.005Ni0.5Mn1.5O4) 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 Li0.995V0.005Ni0.5Mn1.5O4 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 Li0.995V0.005Ni0.5Mn1.5O4 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.

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