不同锰源对富锂正极材料Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2性能的影响

Electrochemical Characteristics of Li-Rich Cathode Material Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2 with Different Manganese Raw Materials

采用MnCO3或MnO2为锰源,设计了两条工艺路线,并分析了这两种工艺对富锂正极材料Li1.2Mn0.54Ni0.13Co0.13O2结构、形貌、振实密度及电化学性能的影响。研究结果表明,两种工艺制备的材料都具有层状结构,二次颗粒都呈球形,球形颗粒的直径都在2~15μm,一次颗粒0.2~1.0μm;但是在两种不同的工艺下,球形颗粒的聚集程度不一,其中以MnO2为锰源,制备的材料的颗粒接触最为紧密,而且其振实密度高,为1.5g·cm-3。以制备出的材料作为电池的正极材料,组装2032扣式电池,在0.1C（20mA·g-1）,电压范围2.0~4.8V,测试材料的首次充放电,其中以MnCO3为锰源,制备的材料的首次放电比容量为最高,为262.1mAh·g-1,首次库伦效率为76.8%。在不同倍率（0.2C,0.5C,1.0C和3.0C）下测试电池性能,以MnO2为锰源,3.0C下的放电比容量为183.5mAh·g-1。因此,采用MnO2为锰源制备出的富锂正极材料具有较高的倍率性能。

Two routes were designed to prepare Li-rich solid solution material Lil 2 Mn0.54Ni0. 13 CO0. 13 O2 with MnCO3 or MnO2 as man- ganese raw materials. After that, the influences of the two different routes on structure, morphology, tap density and electrochemical properties were analyzed. X-ray diffraction （XRD） results showed that the space group of the materials prepared by the two processes was R-3m. The morphology of the two materials was spherical and the diameter of the sphere was 2 - 15 μm. The first particle was 0. 2 - 1.0 ~m. However, the degree of aggregation of particles was different. The particles of the material prepared by MnO2 as manga- nese raw materials contacted closely and its tap density was higher, which was 1.5 g.cm-3. The prepared material was used to assem- ble 2032 button cell as cathode material. The charge/discharge properties of these materials were tested at different rates in the voltage range of 2.0 ~4.8 V. At 0.1C （20 mA.g-1 ）, the first discharge capacity of the material made by the process of using MnCO3 as raw material was the highest, which was 262.1 mAh·g-1. The first coulombic efficiency of this kind of material was 76.8%. It was used to test ceil properties at different current densities （0.2C, 0.5C, 1.0C and 3.0C）. The discharge capacity at 3.0C was 183.5 mAh·g-1. In conclusion, the materials prepared with MnO2 as Mn-raw material had better rate properties.