摘要
以乙酸盐为原料,采用喷雾干燥法制备层状α-NaFeO2结构的富锂正极材料Li[Li0.2Ni0.2Mn0.6]O2及掺杂Cr的Li[Li0.2Ni0.15Cr0.1Mn0.55]O2。采用X射线衍射、扫描电镜、半电池充放电和电化学阻抗谱等方法研究材料的物相、结构、形貌及电化学性能。结果表明:Cr掺杂使材料的颗粒变粗,但不改变材料的结构,而使材料的层状特征更为明显;Cr掺杂后材料的电化学性能得到明显改善,电荷转移阻抗Rct从275.0降低到105.0,循环稳定性和倍率性能均有所改善,Li[Li0.2Ni0.15Cr0.1Mn0.55]O2材料1C倍率下的放电比容量为140.0 mA.h/g,循环50次后放电比容量为133.7 mA.h/g,远高于未掺杂Cr材料的比容量,未掺杂Cr材料在1C倍率下放电比容量为107.1mA.h/g,循环50次后放电比容量为102.1 mA.h/g。
Abstract： Layered Li-rich cathode Li[Li0.2Ni0.2Mn0.6]O2 and Li[Li0.2Ni0.15Cr0.1Mn0.55]O2 materials with a-NaFeO2 structure were prepared by spray-drying method using aqueous solutions of corresponding metal acetates as the reactants. The composition, crystalline structure, morphology and electrochemical properties of the as-prepared materials were characterized by XRD, SEM and half cell charge-discharge testing and AC impedance. The results show that Cr-doping increases the particle size, Cr-doping does not change the material structure but leads to a better defined, layered structure The Cr-doped material Li[Li0.2Ni0.15Cr0.1Mn0.55]O22 shows better electrochemical performance, it has lower impedance value （105.0Ω） compared with that of the undoped material （275.0 Ω）, better cycle performance and superior rate capability. It delivers the first discharge specific capacity of 140.0 mA.h/g at 1C and the capacity retention of this sample after 50 cycles at 1C rate is 133.7 mA.h/g, while the undoped sample delivers the first discharge specific capacity of 107.1 mA.h/g at 1C and remains 102.1 mA-h/g at 1Crate after 50 cycles.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2013年第4期1047-1052,共6页
The Chinese Journal of Nonferrous Metals
基金
湖南省科技重大专项计划资助项目(2011FJ1005)
