摘要
采用X射线衍射(XRD)、透射电镜(TEM)和电化学方法,研究Ni2+掺杂对正极材料Li3V2(PO4)3的结构、形貌和电化学性能的影响。结果表明:掺杂适量的Ni2+不会改变Li3V2(PO4)3的单斜晶系结构,但可提高材料的电导率,抑制电池在充放电过程的极化。在室温下,Li3(Ni0.05V0.95)2(PO4)3以0.1C倍率放电的初始比容量为115mA.h/g,放电倍率从0.1C增加到0.4C循环60次后,比容量衰减率仅为2.7%,而未掺杂原样Li3V2(PO4)3的初始比容量为129 mA.h/g,60次循环后比容量衰减率约为30.3%;当放电倍率增至1C时,80次循环后,Li3(Ni0.05V0.95)2(PO4)3比容量为99.8 mA.h/g,而原样的比容量为84.1 mA.h/g;当放电倍率增至5C时,循环120次后,Li3(Ni0.05V0.95)2(PO4)3比容量为67.7 mA.h/g,而原样的比容量降为0。循环伏安和交流阻抗测试表明,Li3(Ni0.05V0.95)2(PO4)3的可逆性明显优于Li3V2(PO4)3的可逆性。
The effects of Ni2＋ doping on the structure,morphology and electrochemical performance of cathode material Li3V2（PO4）3 were studied by X-ray diffractometry（XRD）,transmission electron microscopy（TEM） and electrochemical method.The results indicate that the monoclinic structure of Li3V2（PO4）3 is not changed while the conductivity increases and the polarization of the battery is restrained during charge-discharge process due to doping appropriate amount of Ni2＋. Li 3（Ni 0.05 V 0.95） 2（PO4）3 has an initial specific capacity of 115 mA·h/g at 0.1C discharging at room temperature and the specific capacity only decreases by 2.7% after 60 cycles when the discharging rate changes from 0.1C to 0.4C.However, the raw sample Li3V2（PO4）3 has an initial specific capacity of 129 mA·h/g and the specific capacity decreases by 30.3% after 60 cycles.Furthermore,when the discharging rate increases to 1C,the specific capacity of Li 3（Ni 0.05-V 0.95） 2（PO4）3 decrease slightly to 99.8 mA·h/g after 80 cycles,while the specific capacity of the raw sample declines considerably to 84.1 mA·h/g.When the discharging rate increases to 5C,the specific capacity of Li 3（Ni 0.05 V 0.95） 2（PO4）3 decreases to 67.7 mA·h/g after 120 cycles,while the specific capacity of the raw sample declines to 0.Additionally,the tests of cyclic voltammogram and AC impedance show that the reversibility of Li 3（Ni 0.05 V 0.95） 2（PO4）3 is obviously better than that of Li3V2（PO4）3.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2012年第11期3144-3150,共7页
The Chinese Journal of Nonferrous Metals
基金
安徽省教育厅自然科学研究项目(050601D2)
