The effects of Ni/Co ratios on A2B7-type La0.7Mg0.3 (Ni1-xCox)3.5 （0≤x≤0.5） alloys were investigated. The results showed that the discharge capacity of the alloys first increased from 245 to 392 mAh·g-1, then...The effects of Ni/Co ratios on A2B7-type La0.7Mg0.3 (Ni1-xCox)3.5 （0≤x≤0.5） alloys were investigated. The results showed that the discharge capacity of the alloys first increased from 245 to 392 mAh·g-1, then decreased to 316 mAh·g-1, corresponding to x=0, 0.2 and 0.5, respectively. While the electrochemical impedance spectra indicated that the reaction resistance had the opposite tendency. When x is equal to 0.2, the reaction resistance has the lowest value. The electrochemical P-C-T results are consistent with the discharge ones of the alloys. When x is equal to 0.2, the dehydriding capacity is 1.34wt.%.展开更多
以综合电化学性能较佳的低镁含量合金La0.64Gd0.2Mg0.16Ni3.1Co0.3Al0.1为基础,通过改变Mg元素含量的添加方式,用感应熔炼方法与热处理制备了La0.64Gd0.2Mg0.16（1＋x）Ni3.1Co0.3Al0.1系列合金,系统研究了该条件下镁元素成分波动（Mg...以综合电化学性能较佳的低镁含量合金La0.64Gd0.2Mg0.16Ni3.1Co0.3Al0.1为基础,通过改变Mg元素含量的添加方式,用感应熔炼方法与热处理制备了La0.64Gd0.2Mg0.16（1＋x）Ni3.1Co0.3Al0.1系列合金,系统研究了该条件下镁元素成分波动（Mg过量值x）对La-Mg-Ni系A2B7型合金微观结构和电化学性能的影响规律。合金相结构分析表明,合金退火组织由主相Ce2Ni7（Gd2Co7）型以及Pr5Co19型、Pu Ni3型和Ca Cu5型多相组成,随Mg过量值x增加,合金中主相Ce2Ni7型相丰度呈现先增加后减小的趋势;当Mg过量值0〈x≤50%时,合金组织的Ce2Ni7型主相相丰度达到81.04%~87.18%;x=0,80%时,Ce2Ni7型主相丰度减小至76.3%以下。电化学测试结果表明,随Mg过量值x增加,合金电极最大放电容量呈先增加后降低趋势,x=10%时合金具有最高电化学放电容量（384.6 m Ah·g-1）;当Mg过量值x在5%~50%范围内变化时,其电极循环稳定性均保持在S100≥90%,此时镁元素成分波动变化对合金电极循环稳定性的影响不敏感。合金电极的高倍率放电性能（HRD）随Mg过量值的增加呈先增大后减小趋势,其中电极表面的电荷转移速率是影响合金电化学反应动力学性能的主要控制步骤。展开更多
文摘The effects of Ni/Co ratios on A2B7-type La0.7Mg0.3 (Ni1-xCox)3.5 （0≤x≤0.5） alloys were investigated. The results showed that the discharge capacity of the alloys first increased from 245 to 392 mAh·g-1, then decreased to 316 mAh·g-1, corresponding to x=0, 0.2 and 0.5, respectively. While the electrochemical impedance spectra indicated that the reaction resistance had the opposite tendency. When x is equal to 0.2, the reaction resistance has the lowest value. The electrochemical P-C-T results are consistent with the discharge ones of the alloys. When x is equal to 0.2, the dehydriding capacity is 1.34wt.%.
文摘以综合电化学性能较佳的低镁含量合金La0.64Gd0.2Mg0.16Ni3.1Co0.3Al0.1为基础,通过改变Mg元素含量的添加方式,用感应熔炼方法与热处理制备了La0.64Gd0.2Mg0.16（1＋x）Ni3.1Co0.3Al0.1系列合金,系统研究了该条件下镁元素成分波动（Mg过量值x）对La-Mg-Ni系A2B7型合金微观结构和电化学性能的影响规律。合金相结构分析表明,合金退火组织由主相Ce2Ni7（Gd2Co7）型以及Pr5Co19型、Pu Ni3型和Ca Cu5型多相组成,随Mg过量值x增加,合金中主相Ce2Ni7型相丰度呈现先增加后减小的趋势;当Mg过量值0〈x≤50%时,合金组织的Ce2Ni7型主相相丰度达到81.04%~87.18%;x=0,80%时,Ce2Ni7型主相丰度减小至76.3%以下。电化学测试结果表明,随Mg过量值x增加,合金电极最大放电容量呈先增加后降低趋势,x=10%时合金具有最高电化学放电容量（384.6 m Ah·g-1）;当Mg过量值x在5%~50%范围内变化时,其电极循环稳定性均保持在S100≥90%,此时镁元素成分波动变化对合金电极循环稳定性的影响不敏感。合金电极的高倍率放电性能（HRD）随Mg过量值的增加呈先增大后减小趋势,其中电极表面的电荷转移速率是影响合金电化学反应动力学性能的主要控制步骤。
