Influence of doped elements on electrochemical high temperature performance of La-riched hydrogen storage material

Abstract

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.

Keywords

doped elements / metal hydride electrode / electrochemical performance

References

[1] Reilly J J, Adzic G D, Johnson J R, Vogt T, Mukerjee S. The Correlation Between Composition and Electrochemical Properties of Metal Hydride Electrodes. Journal of Alloys & Compounds, 1999, 293–295: 596-600.

[2] Sakai T, Yoshinaga H, Miyamura H, kuriyama N. Rare Earth Based Hydrogen Storage Alloys for Rechargeable Nickel Metal Hydride Batteries. Journal of the Less-common Metal, 1990, 159: 127-131.

[3] Gifford Paul, Adams John, Corrigan Dennis, Venkatesan Srinivasan. Development of Advanced Nickel/metal Hydride Batteries for Electric and Hybrid Vehicles. Journal of Power Sources, 1999, 80: 157-163.

[4] Leblanc Patrick, Blandchard Philippe, Stephane Senyarich. Self-discharge of Sealed Nickel-metal Hydride Batteries. Journal of the Electrochemical Society, 1998, 145(3): 844-847.

[5] Geng Mingming, Han Jianwen, Feng Feng, Northwood Dered O. Charging/discharging Stability of a Metal Hydride Battery Electrode. Journal of the Electrochemical Society, 1999, 146(7): 2371-2375.

[6] Rand D A J, Woods R, Dell R M. Betteries for Electric Vehicles, 1999, Porking: UK & International Press.

[7] Sakai T, Yoshinaga H, Miyamura H. Some Factors Affecting the Cycle Lives of LaNi₅-based Alloy Electrodes of Hydrogen Batteries. Journal of Alloys & Compounds, 1992, 180: 37-54.

[8] Nottern P H L, Hokeling P. Double-phase Hydride Forming Compounds: a New Class of Highly Electrocatalytic Materials. Journal of the Electrochemical Society, 1991, 138(7): 1877-1885.

[9] Weaver J H. Effect of Rare Earth Composition on the Electrochemical Properties of Mm(Ni−Mn−Al−Co)₅ Alloy. Journal of the Appied Physics, 1988, 51: 5847-5851.

[10] Wang X-L, Suda S. Effects of Al-substitution on Hydriding Reaction Rates of LaNi₅− _xAl _x. Journal of Alloys & Compounds, 1993, 191: 5-7.

[11] Matusuoka Masao, Asai Katsuhiko, Asai Kazuaki, Fukunoto Yukio. Electrochemical Characterization of Surface-modified Negative Electrodes Consisting of Hydrogen Storage Alloys. Journal of Alloys & Compounds, 1993, 192: 149-51.