加压氧化法制备LiNi0.8Co0.15Al0.05O2正极材料

摘要

以控制结晶法合成的球形 Ni0.8Co0.15Al0.05(OH)2.05为前驱体，采用加压氧化法制备锂离子电池正极材料LiNi0.8Co0.15Al0.05O2。利用X射线衍射(XRD)、扫描电镜(SEM)和恒电流充放电测试等方法对该材料的结构、形貌及电化学性能进行表征。考察氢氧化锂与前驱体物质的量之比(锂配比)、在煅烧过程中的压力、温度和时间等因素对LiNi0.8Co0.15Al0.05O2材料结构及性能的影响。结果表明：锂配比为1.02时，在0.4 MPa氧气压力下，于700℃煅烧10 h制备的材料具有最完善的结构和最好的电化学性能；在2.8~4.3 V电压范围内，以0.2 C进行充放电，首次放电比容量达到190.1 mA∙h/g，50次循环后容量保持率为90.2%，同时显示出良好的倍率性能和高温性能。%The cathode materials LiNi0.8Co0.15Al0.05O2 were synthesized under elevated oxygen pressure from spheric Ni0.8Co0.15Al0.05(OH)2.05 prepared by controlled crystallization method. The materials were characterized by X­ray diffractometry (XRD), scanning electron microscopy (SEM) and galvanostatic charge­discharge tests. The effects of molar ratio of Li to Ni+Co+Al, oxygen pressure, temperature and time during calcining on the material structure and electrochemical properties of LiNi0.8Co0.15Al0.05O2 were examined. The results show that, under the conditions of the molar ratio of Li to Ni+Co+Al of 1.02, oxygen pressure of 0.4 MPa, temperature of 700℃and time of 10 h, the obtained material exhibits the most ordered structure and the best electrochemical performance. The initial discharge specific capacity of the material is 190.1 mA∙h/g at 0.2 C in the voltage range of 2.8−4.3 V, and after 50 cycles, 90.2% of the initial discharge capacity of the material is maintained. Besides, the material also exhibits excellent rate capability and high­temperature performance.