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采用中频感应熔炼-快淬方法制备了La17Fe3Mn5Al2Ni73-xBx(x=0,1,3,5)储氢合金。结构分析表明,不含B的合金为双相结构,主相为LaNi5相,第二相为La2Ni7相,含B合金均由LaNi5相、La2Ni7相和La3Ni13B2相组成,且随着B含量的增加,LaNi5相和La2Ni7相减少,La3Ni13B2相逐渐增加。电化学测试表明,随着B含量的增加,合金的活化性能、最大放电容量不同程度下降,而循环稳定性有所改善。合金电极的倍率放电能力(HRD)随着B含量的增加呈先增大后减小的趋势,表明适量的B有利于提高合金的高倍率放电性能。合金电极的交换电流密度(I0)随着B含量的增加先增大后减小,而氢在合金中的扩散系数(D)则逐渐增大,表明合金的高倍率放电性能主要取决于合金表面的电荷转移能力。
La17Fe3Mn5Al2Ni73-xBx (x = 0,1,3,5) hydrogen storage alloys were prepared by IF induction melting-quenching method. The structural analysis shows that the alloy without B is a dual phase structure, the main phase is LaNi5 phase, the second phase is La2Ni7 phase, the alloy containing B consists of LaNi5 phase, La2Ni7 phase and La3Ni13B2 phase. With the increase of B content, LaNi5 phase and La2Ni7 phase decreased, La3Ni13B2 phase gradually increased. Electrochemical tests show that with the increase of B content, the activation performance and the maximum discharge capacity of the alloy decrease to different degrees, but the cycle stability is improved. The rate discharge capacity (HRD) of alloy electrode firstly increases and then decreases with the increase of B content, indicating that proper amount of B is beneficial to improve the high rate discharge performance of the alloy. The exchange current density (I0) of the alloy electrode first increases and then decreases with the increase of B content, while the diffusion coefficient (D) of hydrogen in the alloy gradually increases, indicating that the high-rate discharge performance of the alloy mainly depends on the alloy surface Charge transfer ability.