Electrochemical hydrogen-storage properties of La_(0.78)Mg _(0.22)Ni2.67Mn_(0.11)Al_(0.11)Co _(0.52)-M1Ni_(3.5)Co_(0.6)Mn_(0.4)Al _(0.5) composites

摘要

For improving the electrochemical properties of nonstoichiometric AB _3-type La_(0.78)Mg_(0.22)Ni_(2.67)Mn _(0.11)Al_(0.11)Co_(0.52) alloy as negative electrode of Ni-MH battery, its related composites La_(0.78)Mg_(0.22)Ni _(2.67)Mn_(0.11)Al_(0.11)Co_(0.52)-x wt.% M1Ni_(3.5)Co_(0.6)Mn_(0.4)Al_(0.5) (x = 0, 10, 20, 30) were prepared. Analysis by X-ray diffractometry (XRD) revealed that the composites consist mainly of LaNi_5 and La_2Ni_7 phases. Despite the small decrease in the maximum discharge capacity, the cycle performance was significantly enhanced. Linear polarization (LP), anodic polarization (AP) and potential step discharge experiments revealed that the electrochemical kinetics increases first and then decreases with increasing x.