Electrochemical behavior of a spinel zinc ferrite alloy obtained by a simple sol-gel route for Ni-MH battery applications

The hydrogen storage properties of zinc ferrite spinel (ZnFe2O4) alloy were
studied, in this work. This alloy, formed applying the sol-gel technique, was
employed as anode in Ni-MH accumulators. X-ray diffractogram analysis
showed the appearance of the compound spinel with cubic structure. In fact,
the crystallite size, specified by the TEM technique, was equal to 30 nm. The
hydrogen storage properties of zinc ferrite spinel alloy were examined applying
various electromechanical methods (chronopotentiometry, cyclic voltammetry,
and chronoamperometry) at the C/10 rate and at room temperature. The maximum
discharge capacity value was almost equal to 145 mAh/g. After
100 cycles, a good cycling stability was attained and correlation between the
(DH/a2) ratio and the discharge capacity as noticed. The electrolyte/ZnFe2O4
anode interface prior to and following activation was studied utilizing electrochemical
impedance spectroscopy.