Na^+对Li/改性石墨电池循环性能的影响研究

Study on the Effect of Sodium Ion on Cycle Performance of Lithium/Improved Graphite Lithium Ion Cell

分别用普通 4A和锂化 4A分子筛两种方法去除锂离子电池非水电解质体系 (EC/DEC/LiClO4 )中的微量水 ,引进不同浓度的Na+ 离子 .用原子吸收光谱法测定两种情况下体系中的Na+及Li+ 浓度 ;然后于室温下恒电流充放电 ,测定利用上述两种除水方法所得电解液配制的Li/石墨电池的循环性能 .结果表明 ,小电流下充放电 ,高Na+ 浓度能对锂离子电池循环性能构成严重破坏 ;随着电流的增大 ,电池对Na+ 的敏感性降低 .根据对循环后的电极片进行电子扫描实验结果 ,提出了Na+ 对锂离子电池循环性能影响机理的电化学解释 .

The different concentration of Na + was introduced into the non_aqueous eletrolyte system EC/DEC/LiClO 4 with 4A molecular sieve and lithiated 4A molecular sieve,by which the trace amount of water was removed.The concentrations of Na + and Li + were determined by atomic adsorption spectrometry. The cycle performance of lithium/improved graphite cells was then examined by charging and discharging under the constant electric current.The results demonstrated that the cycle performance of the cells was destroyed by the high concentration of Na + under the small electric current.With the increase of electric current,the cell became less sensitive to the concentration of Na +.According to the examination of cycled cathode's surface by SEM,the mechaninsm of sodium ion's effect on cycle performance of lithium ion cell was raised.