Ni3S2-coated metal hydride anode with high-power and long-life performance for low-temperature Ni-MH power batteries

The corrosion or oxidation layers on the surface of hydrogen storage alloy severely obstruct the high-rate and low-temperature performance of the anode, which restricts the applications of nickel metal hydride batteries in high-power fields, extreme environments and national defense. Here a novel method is developed to obtain excellent high-rate and low-temperature performance of metal hydride (MH) anode via the in-situ coating of Ni3S2. Through a facile hydrothermal sulfurization at 120 degrees C, the stable and porous Ni3S2 nanosheets arrays are effectively synthesized on the surface of the hydrogen storage alloys. Attributing to the high electronic conductivity, excellent electrocatalytic activity and structure stability of those Ni3S2 coating layers, the low-temperature, high-power performance and cycling life of our elaborate MH alloy are significantly improved. Notably, the Ni3S2 -coated (LaCe)(1.0)Ni3S2Co0.75Mn0.35Al0.1 alloy with 87.9% of cycling stability maintains a capacity retention rate of 53.6% at 3000 mA g(-1), which is 2.3 times that of the original alloy (23.7%), and at -40 degrees C, the discharge capacity improves to 198.2 mAh g(-1) and P-peak attains to 750.1 W kg(-1). This novel sulfurization technology of hydrogen storage alloy provides a cog-efficient solution for high-power, low-temperature and long-life Ni-MH batteries.