High-performance nickel metal hydride battery anode with enhanced durability and excellent low-temperature discharge capability

Current AB₅-type hydrogen storage alloys employed in nickel-metal hydride (NiMH) batteries exhibit exceptional low-temperature discharge performance but suffer from limited cycle life and insufficient high-temperature stability. To overcome these challenges, we introduce a hydrothermal synthesized LaF₃ coating layer on the surface of the AB₅ anode material. This LaF₃ coating layer adds a protective barrier for the active material, significantly improving the battery's cycle life and high-temperature stability. Our findings indicate that (1) the LaF₃ coated anode demonstrates an extended cycle life with increased specific capacity and a capacity retention of 88% after 40 cycles of abusive overcharging and rapid discharging at room temperature. (2) The synthesized anode exhibits a 97% recovery of its specific capacity of 292.7 mAh/g following 144 h of high-temperature storage. (3) The low-temperature discharge capacity of the synthesized anode remains on par with the pristine AB₅ alloy at 230.4 mAh/g in a –40 °C environment. This research presents a significant advancement in hydrogen storage alloy coatings and offers valuable insights for designing electrodes in NiMH batteries.