氧化铝溶胶改性锂离子电池正负极材料的研究

Study on aluminum sol modified anode and cathode materials for lithium ion batteries

随着电动汽车和清洁能源的发展,对锂离子电池的储能能力和循环寿命提出了更高的要求。采用氧化铝溶胶浸渍-包覆法对NCM811正极材料和G/SiO负极材料进行改性。此方法与硝酸铝浸渍法相比热分解产生的氮氧化物量降低99%以上,相较于沉淀法无副产物,成本低于有机铝盐法,均匀性高于干法混合,易于实现规模化生产。表征发现氧化铝溶胶的加入并不会影响正负极材料的结构和充放电机理。电化学性能测试表明,当氧化铝添加量分别为0.3%和0.7%(质量分数)时,可以分别使得正极材料NCM811和负极材料G/SiO获得最优的倍率性能和循环稳定性能。在1C充放电下,将NCM811和0.3%氧化铝改性的NCM811分别与锂片组装成锂离子电池后循环100次,其容量分别为123.55 mA·h/g和151.02 mA·h/g。在0.1C充放电下,将G/SiO负极和0.7%氧化铝改性的G/SiO负极分别与锂片组装成锂离子电池后循环45次,其容量分别为360.57 mA·h/g和385.06 mA·h/g。

With the development of electric vehicles and clean energy,higher requirements are put forward for the energy storage capacity and cycle life of lithium⁃ion batteries.In this paper,the positive electrode material of NCM811 and the negative electrode material of G/SiO were modified by alumina sol impregnation⁃coating method.Compared with the alumi⁃num nitrate impregnation method,the amount of nitrogen oxides produced by thermal decomposition was reduced by more than 99%.Compared with the precipitation method,there were no by⁃products,the cost was lower than the organoaluminum salt method,and the uniformity was higher than the dry method,and it was easy to achieve scale.It was found that the addi⁃tion of alumina sol did not affect the structure and charge and discharge mechanism of anode and cathode materials.The electrochemical performance test shows that the anode material NCM811 and cathode material G/SiO could obtain the best rate performance and cycle stability when the amount of alumina was 0.3%and 0.7%,respectively.Under 1C charge and dis⁃charge,the NCM811 and 0.3%alumina modified NCM811 were assembled into lithium⁃ion batteries with lithium sheets,and the cycles were 100 times,and the capacities were 123.55 mA·h/g and 151.02 mA·h/g,respectively.At 0.1C charge and discharge,the G/SiO cathode and 0.7%alumina modified cathode were assembled with lithium sheets to form a lithium⁃ion battery and then cycled for 45 times,with a capacity of 360.57 mA·h/g and 385.06 mA·h/g,respectively.