Nickel-Metal-Hydride Battery Electrodes

Nickel hydrogen batteries are well established for use in satellite applications, due to their excellent cycle life, no maintenance and high reliability. These excellent characteristics are mitigated by the use of high pressure vessels for hydrogen storage. Nickel/metal hydride batteries have same chemistry, except for storing the hydrogen as a metal hydride. Ni/M-H batteries are inherently safe and have an energy density of 55 Wh/kg and 178 Wh/L, two to three times that of Ni-Cd batteries. Present state of the art batteries utilize metal hydrides, containing 1-1.2 wt% hydrogen. Worldwide development efforts are in progress to develop nickel/metal hydride batteries. By developing reversible metal hydrides of > 2 wt% hydrogen and appropriate battery design and engineering, the energy density of this system can be enhanced to >100 Wh/kg and 300 Wh/L, making them suitable for many space station battery applications. The proposed Phase I program will (i) research novel metal hydride materials with >2 wt% hydrogen capacity, (ii) establish reversibility and stability and (ii) demonstrate at the cell level superior nickel/metal hydride battery characteristics. The Phase II program will involve design, development, fabrication, and testing of full-size battery configurations.