Influence of Doped Elements on Electrochemical High Temperature Performance of La- riched Hydrogen Storage Material

摘要

The effects of small amounts of added elements such as aluminum, titanium and zirconium to MlNi_(3.8) (CoMn)_(1.2) on its electrochemical performances and performances at high temperatures were investigated. It is found that the addition of aluminum brings about a significant increase in the discharge capacity at high temperatures, and the capacity decay during repeated charge- discharge cycles and the self discharge are both suppressed, while the rate capability decreases. The alloy containing zirconium exhibits a longer cycle life and a better rate capability, but a much lower discharge capacity. The addition of titanium improves the rate capability, but the capacity decreases greatly. An X-ray diffraction analysis indicates that a second phase exists in the alloy with additive Zr or Ti, which improves the discharge- rate characteristics, and the superior stability of the alloy with additive Al may be due to the expansion of lattice parameters and cell volume.