锌掺杂提高LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2正极材料的电化学稳定性(英文)  

Improved Electrochemical Stability of Zn-Doped LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 Cathode Materials

作　　者：李节宾[1,2] 徐友龙[1] 杜显锋[1] 孙孝飞[1] 熊礼龙[1] 

机构地区：[1]西安交通大学,电子陶瓷与器件教育部重点实验室,国际电介质研究中心,西安710049 [2]陕西应用物理化学研究所,西安710061

出　　处：《物理化学学报》2012年第8期1899-1905,共7页Acta Physico-Chimica Sinica

基　　金：supported by the National Natural Science Foundation of China (50902109)~~

摘　　要：通过共沉淀法与固相法相结合制备了掺锌的高稳定性Li(Ni1/3Co1/3Mn1/3)1-xZnxO2(x=0, 0.02, 0.05)正极材料. 循环伏安(CV)曲线表明Zn掺杂使氧化峰与还原峰的电势差减小到0.09 V, 电化学阻抗谱(EIS)曲线表明Zn 掺杂使电极的阻抗从 266 Ω减小到 102 Ω. Li+嵌入扩散系数从1.20×10-11cm2·s-1增大到 2.54×10-11cm2·s-1. Li(Ni1/3Co1/3Mn1/3)0.98Zn0.02O2正极材料以0.3C充放电在较高的截止电压(4.6 V)下比其他两种材料的电化学循环性能更稳定, 其第二周的放电比容量为176.2 mAh·g-1, 室温下循环 100 周后容量几乎没衰减; 高温(55℃)下充放电循环100周, 其放电比容量平均每周仅衰减0.20%, 远小于其他两种正极材料(LiNi1/3Co1/3Mn1/3O2平均每周衰减0.54%; Li(Ni1/3Co1/3Mn1/3)0.95Zn0.05O2平均每周衰减0.38%). Li(Ni1/3Co1/3Mn1/3)0.98Zn0.02O2正极材料以3C充放电时其放电比容量可达142 mAh·g-1, 高于其他两种正极材料. 电化学稳定性的提高归因于 Zn 掺杂后减小了电极的极化和阻抗, 增大了锂离子扩散系数.Highly stable Li（Ni1/3Co1/3Mn1/3）1-xZnxO2 （x=0, 0.02, 0.05） cathode materials doped with Zn are synthesized by solid-state reactions with co-precipitated precursors. Cyclic voltammetry （CV） curves reveal that the potential difference between oxidation and reduction decreases to 0.09 V, and from electrochemical impedance spectra （EIS） curves, the impedance of LiNi1/3Co1/3Mn1/3O2 cathode materials is reduced from 266 to 102 Ω. The diffusion coefficients of Li＋ ions in intercalation processes increase from 1.20×10-11 to 2.54×10-11 cm2·s-1. Li（Ni1/3Co1/3Mn1/3）0.98Zn0.02O2 is stable at 0.3C （constant charge/discharge） at a high cut-off potential of 4.6 V vs Li/Li＋. It has a second discharge capacity of 176.2 mAh·g-1 at 0.3C and 142 mAh·g-1 at 3C, and keep almost no decay after 100 cycles at room temperature. Furthermore, its average capacity loss per cycle at 55 °C is 0.20%, which is lower compared with 0.54% for LiNi1/3Co1/3Mn1/3O2 and 0.38% for Li（Ni1/3Co1/3Mn1/3）0.95Zn0.05O2 after 100 cycles. The improved electrochemical stability of Zn-doped LiNi1/3Co1/3Mn1/3O2 is attributed to the reduced electrode polarization and impedance values, and an increased Li＋ ion diffusion coefficient.

关 键 词：LINI1/3CO1/3MN1/3O2 高截止电压:Zn掺杂:正极材料:锂离子电池 

分 类 号：TM912[电气工程—电力电子与电力传动]