Reversible electrochemical storage of hydrogen in Ti51-xZrxNi49 alloys

The Ti51-xZrxNi49 (0≤x≤24) alloys have been studied for their use as anodes in NiMH battery. The increasing substitution of titanium by zirconium allows to increase the existing range of the martensitic phase. The hydrogenation properties by solid gas way indicates that this phase can absorb until 2.6 hydrogen atoms by AB formula (H/AB). The alloys x=6, 12 and 18 used for hydrogen storage by electrochemical reaction have shown that activation is fast and that discharged capacities are important (330 to 370 mAh/g). Nevertheless, the lifetime of these electrodes is short and can be explained by the formation of a passivation layer. (O.M.)