Effect of Inco Ni powder type 210 and 210H on internal pressure of Ni/metal hydride cells

The effect of high surface area, filamentary Inco nickel powders Type 210 and 210H, and of standard battery grade Ni powder Type 255, on the internal pressure of Ni/metal hydride (MH) cells was studied in starved cells. When used as additive to the Teflon bonded AB₅ metal hydride electrode in a range of 2.5 to 5 wt%, the high surface area powders were found highly effective in accelerating oxygen recombination and suppressing hydrogen evolution and accumulating during overcharge. This led to significantly lower internal pressure in Ni/MeH cells during cycling. The pressure reduction, as well as the MH electrode capacity improvement, was found directly proportional to the specific surface area of the added nickel powder rather than to their ability to improve conductivity. The benefit of the nickel addition is believed to relate to their catalysis to the electrode reactions InNi/MH cell