锂离子电池石墨负极放热反应研究

Research on exothermic reaction of graphite anode for lithium-ion battery

采用差示扫描量热仪(DSC)对满嵌锂态石墨负极在50~400℃之间出现的放热反应进行了研究。对不同荷电状态(SOC)的负极进行DSC、扫描电镜(SEM)和X射线衍射(XRD)分析以研究放热反应发生的过程。对负极中各物质之间可能发生的反应也均使用DSC进行分析。最终得出石墨负极各放热反应归属:100~120℃为SEI膜分解,200~270℃为锂与电解液的反应,270~300℃为锂与羧甲基纤维素钠(CMC)的反应以及电解液的分解反应,300℃以上放热尖峰为锂与石墨的反应。

The exothermic reaction of fully lithiated graphite anode from 50℃to 400℃was studied with differential scanning calorimeter(DSC).Different SOC state anodes were investigated with DSC,SEM and XRD for studying the exothermic reaction process.The DSC was also used to evaluate the reactions of the materials in the anode.Finally,the exothermic reaction of graphite anode is speculated as follows:100-120℃for SEI decomposition;200-270℃for the reaction between Li and electrolyte;270-300℃for the reaction between Li and CMC or electrolyte decomposition;the exothermic peak above 300℃for the reaction between Li and graphite.