摘要
选择SiC复合材料(比容量>600 mAh/g)混合人造石墨为负极,高镍三元正极材料(NCM)为正极,以EC+DMC+EMC(其中EC+DMC+EMC体积比1∶1∶1)为基础电解液,组装成2.83 Ah18650圆柱电池,考察FEC不同添加量对硅碳负极体系全电池性能影响。结果表明:FEC的加入对电池首次放电容量和库伦效率都有一定的提升,因为FEC先于碳酸酯类溶剂在负极表面形成薄且稳定的SEI膜,抑制碳酸酯类溶剂的分解及Si负极的氧化,其产物具有良好的柔性对Si负极体积膨胀具有一定的缓冲作用。经过对比,加入8%以上FEC电解液的电池表现出了较好的综合性能,首次放电容量达到2.848 Ah,库伦效率82.8%,循环100周后容量保持率97.8%。
The 2.83Ah18650 cylindrical battery was assembled by using SiC composite(specific capacity>600 mAh/g)mixed with artificial graphite as the negative electrode,high nickel ternary positive material(NCM)as the positive electrode,and EC+DMC+EMC(volume ratio 1∶1∶1)as the basic electrolyte,and the effects of different FEC additions on the performance of the whole battery were investigated.The results show that the addition of FEC can improve the first discharge capacity and coulomb efficiency of the battery,because FEC can form a thin and stable SEI film on the surface of the negative electrode before the carbonate solvent,inhibit the decomposition of the carbonate solvent and the oxidation of the Si negative electrode,and the product has a good flexibility,which has a certain buffer effect on the volume expansion of the Si negative electrode.By comparison,the battery with more than 8% FEC electrolyte shows better comprehensive performance,that is,the first discharge capacity is 2.848 Ah,the coulomb efficiency is 82.8%,and the capacity retention rate is 97.8%after cycle100 weeks.
作者
范瑞娟
郑德英
张丁
胡秋晨
FAN Rui-juan;ZHENG De-ying;ZHANG Ding;HU Qiu-chen(New Energy Technology Institute,Shaanxi Coal Chemical Industry Technology Research Institute Co.,Ltd.,Xi’an,710065,China)
出处
《陕西煤炭》
2020年第S01期65-69,共5页
Shaanxi Coal
基金
陕西省重点研发计划《高性能动力电池制造工艺及关键组成匹配性研究》(2017ZDCXL-GY-08-03)。
关键词
硅碳负极材料
FEC添加剂
锂离子电池
silicon carbon anode material
FEC additive
lithium ion battery
