New hydride-forming materials : challenges towards a new generation of high energy density Nickel-Metal-Hydride batteries

The new mathematical model to estimate volumetric and gravimetric energy densities of the rechargeable NiMH batteries has been proposed. Application of the new prospective Mg0.80Sc0.20 (1740 mAh/g) hydride forming material for MH electrode has been studied with the help of that model. It was shown that application of the new Mg0.80Sc0.20 material gives 58 % advance in gravimetric energy density (Wh/kg) for AA-size battery those expected capacity reaches 3045 mAh. For the battery having the same weight as normal AA-size battery higher gains have been achieved, namely, 5 % increase in volumetric energy density and 80 % in gravimetric. Thus prospective NiMH battery may compete with majority of the currently available lithium-ion batteries. The new binary (e.g. Mg-Ti) and ternary (e.g. Mg-Ti-Al) alloys having the same capacity as MgSc alloys can be implemented on a large industrial scale instead of expensive MgSc materials.