新能源汽车电池用无镁储氢合金的制备与性能研究

Study on preparation and properties of magnesium free hydrogen storage alloys for new energy vehicle batteries

采用真空电弧熔炼和925℃/12 h退火的方法制备了Y_(1-x)La_(x)Ni_(3.25)Al_(0.15)Mn_(0.15)储氢合金(x=0~1),研究了x值对储氢合金物相组成和电化学性能的影响。结果表明,x=0和0.15的储氢合金主要由LaNi_(5)和Ce_(2)Ni_(7)相组成,x=0.25、0.33和0.5储氢合金主要由Ce_(5)Co_(19)和Ce_(2)Ni_(7)相组成,x=0.75和1储氢合金主要由PuNi_(3)、LaNi_(5)和Ce_(2)Ni_(7)相组成;相同充放电循环周次下,x=0.15~1储氢合金的放电容量和抗氢致非晶化能力都高于x=0储氢合金,且随着x从0增加至1,储氢合金的最大放电容量(C_(max))、容量保持率(S_(100))、氢扩散系数(D_(0))和高倍率放电性(HRD_(900))都呈现先增加后减小趋势,在x=0.33时取得C_(max)、S_(100)、D_(0)和HRD_(900)最大值。Y_(1-x)La_(x)Ni_(3.25)Al_(0.15)Mn_(0.15)储氢合金的循环稳定性与合金电极的耐腐蚀性密切相关,高倍率放电性能取决于储氢合金的氢扩散速率。

Y_(1-x)La_(x)Ni_(3.25)Al_(0.15)Mn_(0.15)hydrogen storage alloy(x=0~1) was prepared by vacuum arc melting and annealing at 925℃for 12 h.The effect of x value on the phase composition and electrochemical properties of hydrogen storage alloy was studied.The results showed that hydrogen storage alloys with x=0 and 0.15 were mainly composed of LaNi_(5)and Ce_(2)Ni_(7)phases;hydrogen storage alloys with x=0.25,0.33 and 0.5 were mainly composed of Ce_(5)Co_(19)and Ce_(2)Ni_(7)phases;hydrogen storage alloys with x=0.75 and 1 were mainly composed of PuNi_(3),LaNi_(5)and Ce_(2)Ni_(7)phases;under the same charge discharge cycle,the discharge capacity and anti hydrogen induced amorphization ability of hydrogen storage alloy with x=0.15~1 were higher than that of hydrogen storage alloy with x=0,and with the increase of x value from 0 to 1,C_(max),S_(100),D_(0)and HRD_(900)of hydrogen storage alloy increased at first and then decreased,and the maximum values of C_(max),S_(100),D_(0)and HRD_(900)were obtained at x=0.33.The cycle stability of Y_(1-x)La_(x)Ni_(3.25)Al_(0.15)Mn_(0.15)hydrogen storage alloy was closely related to the corrosion resistance of the alloy electrode,and the high rate discharge performance depended on the hydrogen diffusion rate of the hydrogen storage alloy.