摘要
利用电弧熔炼法制备了元素取代前后的Y2FeSb2合金。XRD结果表明,未取代的合金由单一的YSb相组成,La部分取代Y使合金的晶格常数增加,而Ni部分替代Sb的合金由主相YSb相和少量的YNi2、YNi相组成,同时主相的晶格常数也略有增加。电化学测试表明,以Ni粉为导电剂时,La部分取代Y使合金的放电容量有所下降,从34.8 mAh/g下降到了27.3 mAh/g,而Ni替代Sb使合金的放电容量从34.8 mAh/g增加到了51.3 mAh/g,同时使放电电压提高了20 mV,La和Ni同时替代使二者增加的幅度更加明显,特别是放电电压在第50次循环后提高了约300 mV。当Cu粉为导电剂时,Y2FeSb2合金表现出了较大的放电容量(792.6 mAh/g),而La和Ni同时替代后的Y1.5La0.5FeSbNi合金放电容量更是达到了880.8 mAh/g,这主要是由于合金粉和Cu粉在充放电过程中相互作用的缘故。
Y_2FeSb_2alloys with and without elements substitution were prepared by arc melting. XRD results show that Y_2FeSb_2alloy not substituted by other elements consists of a single YSb phase and the lattice parameter increases when La partially substitutes Y. The alloy of Ni substituting partial Sb is composed of matrix phase YSb and a few YNi2and YNi phases and the lattice parameter increases slightly with the substitution of Ni for Sb. The electrochemical testing shows that when using Ni powder as the conductive agent,the discharge capacity of the alloy decreases from 34. 8 mAh / g to 27. 3 mAh / g with La substituting partial Y and increases from 34. 8 mAh / g to 51. 3 mAh / g with Ni substituting partial Sb. At the same time,the discharge voltage of the alloy improves 20 mV with Ni substituting partial Sb. It is more effective for improving the discharge capacity and voltage of the alloy electrode when La and Ni substitute Y and Sb synchronously,especially,the discharge voltage improves about 300 mV after 50 cycle times. When Cu powder as the conductive agent,the discharge capacity of Y_2FeSb_2alloy and Y1. 5La0. 5FeSbNi alloy respectively reach to 792. 6 mAh / g and 880. 8 mAh / g,which is because that electrochemical reaction accurs between the alloy powder and Cu powder in the charge and discharge process.
出处
《稀土》
EI
CAS
CSCD
北大核心
2014年第1期1-5,共5页
Chinese Rare Earths
基金
国家自然科学基金资助项目(51061001)
内蒙古自然科学基金项目(2012MS0808)
国家国际科技合作项目(2013DFR50940
2010DFB63510)
