【作者】 叶尚云； 张平伟； 夏永姚； 乔芝郁；

【Author】 Ye Shangyun, Zhang Pingwei, Xia Yongyao , Qiao Zhiyu (Department of Physics and Chemistry, University of Science and Technology, Beijing 100083, China; Geijiu Superhoo Industries Co. Ltd., Yunnan 661000, China; Department of Chemistry, Fudan University, Shanghai 200433, China)

【机构】 北京科技大学物理化学系； 个旧圣比和实业有限公司； 复旦大学化学系；

【摘要】 用循环伏安法和交流阻抗分析考察了层状Li[(Ni1/3Co1/3Mn1/3)0．96Al0.02B0.02]O1.98F0.02锂离子电池正极材料的电化学反应和充放电过程中的动力学。与Li[Ni1/3Co1/3Mn1/3]O2化合物相比,充放电过程中Li[(Ni1/3Co1/3Mn1/3)0.96Al0.02B0.02]O1.98F0.02化合物的可逆性好,高充电电压下电化学极化小,因此电化学性能得到显著改善,可以提高充电电压到4．7 V而获得190 mAh／g的可逆放电容量。XPS分析表明 Li[(Ni1/3Co1/3Mn1/3)0.96Al0.02B0.02]O1.98F0.02化合物中F,Ni,Co,Mn的氧化态分别为+1,+2,+3和+4,Al,F,B混合掺杂能够抑制化合物表面杂质Li-O化合物的生成。更多还原

【Abstract】 The electrochemical behavior of layer Li[(Ni1/3Co1/3Mn1/3)0.96Al0.02B0.02]O1.98F0.02 cathode was elucidated by the application of cyclic voltammetry(CV) and electrochemical impedance spectrum technology(EIS) compared with the un-doped Li(Ni1/3Co1/3Mn1/3)O2. According to the data of CV and EIS,the Li[(Ni1/3Co1/3Mn1/3)0.96Al0.02B0.02]O1.98F0.02 cathode shows the better electrochemical reversibility of Li-ion intercalation, specially in the high voltage region due to low electrochemical poraizations. It deliverlers a reversible capacity of 190 mAh/g with an excellent cycle ability when charged to 4.7 V vs. Li+/Li. The X-ray photoelectron spectroscopy (XPS) analysis indicate that formal charges of Ni, Coand Mn in Li[(Ni1/3Co1/3Mn1/3)0.96Al0.02B0.02]O1.98F0.02 are , respectively, estimated to be +2, +3, and 44. Al, F and B dopants can restrain the formation of Lithum salts (such as Li2CO3) on the surface of the particles effectively.更多还原