(中南大学 冶金科学与工程学院，长沙 410083)
摘 要: 以共沉淀法制备的球形Ni0.5Co0.3Mn0.2CO3粉末为前驱体，按一定的比例将碳酸锂与前驱体混合，然后采用高温固相法合成高振实密度球形LiNi0.5Co0.3Mn0.2O2正极材料。该材料的振实密度达到2.60 g/cm3，与商品化LiCoO2的密度相当。SEM分析表明， LiNi0.5Co0.3Mn0.2O2正极材料与前驱体形貌有良好的继承性，均为理想的球形。XRD物相分析表明，在不同合成温度下的Li Ni0.5Co0.3Mn0.2O2产物均为具有α-NaFeO2层状结构的纯相物质，在较高合成温度下所得材料的结晶度较高。电化学性能研究表明，在2.7~4.3 V的电压范围内，电池的放电比容量在0.2C倍率下为168.1 mA∙h/g，在1C倍率下为157.6 mA∙h/g；经50次循环后，两种放电条件下的电池容量保持率分别为95.1%和97.2%，显示出良好的电化学性能。
关键字: 锂离子电池；正极材料；振实密度；Li Ni0.5Co0.3Mn0.2O2
（School of Metallurgical Science and Engineering Central South University, Changsha 410083, China）
Abstract:The high tap-density spherical LiNi0.5Co0.3Mn0.2O2 cathode materials were synthesized from coprecipitated Ni0.5Co0.3Mn0.2CO3 by high-temperature solid-state method. The tap-density of the material is as high as 2.60 g/cm3, which is similar to commercial LiCoO2. The SEM results reveal that the LiNi0.5Co0.3Mn0.2O2 cathode material has well kept the spherical morphology of the spherical precursor. The XRD results show that all the LiNi0.5Co0.3Mn0.2O2 samples have high purity phase, and the powders are much better crystallized at higher synthesis temperature. At 2.7−4.3 V, the discharge capacities reach 168.1 and 157.6 mA∙h/g at the rates of 0.2C and 1C, respectively. The capacity retentions after 50 cycles at 0.2C and 1C are 95.1% and 97.2%, respectively. This proves that the materials present excellent electrochemical performances.
Key words: Li-ion battery; cathode material; tap-density; Li Ni0.5Co0.3Mn0.2O2
