锂离子电池正极材料xLi2MnO3·(1-x)LiNi1/3Mn1/3Co1/3O2的制备及表征

摘要

以过渡金属乙酸盐和乙酸锂为原料,柠檬酸为螯合剂,通过溶胶-凝胶法结合高温煅烧法制备了锂离子电池富锂锰基正极材料xLi2MnO3·(1 -x)Li[Ni1/3Mn1mCo1/3]O2,采用X射线衍射(XRD),扫描电子显微镜(SEM)和电化学性能测试对所得样品的结构,形貌及电化学性能进行了表征.结果表明:x=0.5时,在900℃下煅烧12h得到颗粒均匀细小的层状xLi2MnO3·(1 -x)Li[Ni1/3Mn1/nCo1/3]O2材料,并具有良好的电化学性能,在室温下以20mA· g-1的电流密度充放电,2.0-4.8V电位范围内首次放电比容量高达260.0 mAh·g-1,循环40次后放电比容量为244.7 mAh·g-1,容量保持率为94.12％.%The lithium rich cathode materials xLi2Mn03 (I-xJLifNii/sMn^CoioJOz (x=0.4, 0.5, 0.6) were successfully synthesized via sol-gel method with calcination in air. The transition metal acetate, lithium acetate, and citric acid were used as raw materials. The as-prepared materials were characterized by X-ray diffraction (XRD), scaning electron microscopy (SEM), and electrochemical tests. The material 0.5Li2MnO3' 0.5LiNiiraMni/3COio]O2, which was obtained after calcination at 900 °C for 12 h, exhibited fine microstructures and good electrochemical performance. When cycled at 2.0-4.8 V with a current density of 20 Ma-g"1 at room temperature, 0.5Li2MnO3'0.5LiNii/3lv1ni/3Coi/3]C>2 delivered a initial discharge specific capacity of 260.0 mAh-g"1, and maintained a capacity of 244.7 mAh-g"1 after 40 cycles (capacity retention 94.12%).