稀土氧化物对贮氢合金电极电化学性能的影响

研究了稀土氧化物La_2O3_,CeO_2,Nd_2O_3和Y_2O_3对AB_5型贮氢电极电化学性能的影响。研究表明,除Y2_O3_外,其余的稀土氧化物可提高贮氢电极的1C放电容量和放电电压,延长贮氢电极的循环寿命,且对贮氢电极性能有利的顺序为:La2_O3_>CeO2_>Nd2_O3_;稀土氧化物添加量越多,贮氢电极的循环稳定性越好,但对贮氢电极的1C放电容量和放电电压的影响存在最佳值。造成这些结果的原因是:稀土氧化物增大贮氢合金颗粒间的接触电阻;稀土氧化物的催化作用;稀土氧化物对镍催化剂的稳定作用及抑制贮氢合金进一步氧化的作用。

Effect of Rare Earth Oxides on the Electrochemical Performance of Hydrogen Storage Electrode

The effect of rare earth oxides, that is, La2O3,CeO2,Nd2O3 and Y2O3, on the electrochemical performance of hydrogen storage electrode was investigated. The results show that the four rare earth oxides, except Y2O3, are all beneficial to the electrochemical performance of the hydrogen storage electrode, including activation, high rate discharge, discharge voltage and cycle life. For the cycle life, the more the rare earth oxides, the better the cycle life is; but there exists an optimum value of the oxides for the 1 C discharge capacity and discharge voltage, The results are due to three reasons: (1) rare earth oxides increase the contact resistance among the hydrogen storage alloy particles; (2) rare earth oxides have catalysis; (3) rare earth oxides can stabilize the catalyst Ni on the surface of hydrogen storage alloy and prevent the hydrogen storage alloy from being further oxidized.