High-temperature characteristics of advanced Ni-MH batteries using nickel electrodes containing CaF2

The high-temperature charge acceptance of Ni-MH batteries has been improved through the addition of calcium fluoride to the pasted nickel hydroxide electrode made using spherical Co(OH)2-coated nickel hydroxide powder. The charge acceptance of the Ni-MH battery at 60 °C is over 95% at 1 C charge/discharge rates. The charge acceptance at 60 °C remains at over 90% through 10 cycles. The use of Co(OH)2-coated Ni(OH)2 plus a CaF2 addition to the positive electrode also significantly improved the high-temperature stability in terms of reduced gas evolution.