Electrochemical properties of M1Ni_(3.5)Co_(0.6)Mn_(0.4)Al_(0.5)–x wtMm_(0.89)Mg_(0.11)Ni_(2.97)Mn_(0.14)Al_(0.20)Co_(0.54)composites

摘要

In order to improve the overall electrochemical properties of AB5-type storage alloys, the new type composite alloys M1Ni3.5Co0.6Mn0.4Al0.5–x wt% Mm0.89-Mg0.11-Ni2.97Mn0.14Al0.20Co0.54(x = 0, 5, 10; M1 means mischmetal) were prepared by means of ball milling. The composite alloys are shown to be single La Ni5 phase by X-ray diffraction(XRD) patterns. The maximum discharge capacity slightly increases from 315 m Ah g-1for M1Ni3.5Co0.6Mn0.4Al0.5to 324 m Ah g-1(x = 5) and325 m Ah g-1(x = 10). The addition of AB3-type La–Mg–Ni-based alloy has a positive effect on the cycle stability.With the addition of Mm0.89Mg0.11Ni2.97Mn0.14-Al0.20Co0.54 alloy, the exchange current density(I0), the limiting current density(IL), and the diffusion coefficient of hydrogen(D) of the alloy electrodes increase, leading to a corresponding improvement of the high rate dischargeability.