三元锂离子电池氢气产生原因探索  

Exploration of the cause of hydrogen generation in NCM lithium-ion batteries

作　　者：袁雪芹 杨雷[1] YUAN Xueqin;YANG Lei(West Anhui University,Liu'an 237012,Anhui,China)

机构地区：[1]皖西学院,安徽六安237012

出　　处：《储能科学与技术》2021年第1期150-155,共6页Energy Storage Science and Technology

基　　金：安徽省自然科学基金(1908085QE180);皖西学院校级自然重点项目(WXZR202012);安徽省大学生创新创业训练项目(S202010376132)。

摘　　要：本工作通过气相色谱(GC)和可充电对称锂离子电池探索了三元锂离子电池(LIBs)中H2产生的原因。除了公认的氢气是由电池中微量水分还原产生之外,本工作则主要是探索质子电解质氧化物(R-H+)和碳酸酯解离成H∙两种氢气产生机理对于三元锂离子电池是否成立。鉴于R-H+作为正负极间的关联产物沉积在负极表面,分别制备了具有充放电能力的石墨/石墨负极软包对称电池、NCM/NCM(LiNi0.6Co0.2Mn0.2O2被定义为NCM)正极软包对称电池以及石墨/NCM软包全电池,经过常温循环以及过充测试后,GC结果显示H2产生于软包全电池以及负极对称电池,而正极对称电池中没有。此结果侧面验证了R-H+机理成立,即H2由正极端生成沉积在负极表面的产物R-H+还原所产生,因此单独的正极对称电池无H2产生。为了排除电池中微量水分还原产生氢气对R-H+机理验证的干扰,选择循环以后未产生氢气的正极对称电池,加入微量水分再循环后,GC结果检测到氢气。说明对称电池中原本微量水分对最终产生氢气的结果影响可忽略不计。最后,选择了正极对称电池对碳酸酯解离成H∙产氢机理进行验证,根据前面的实验结论,此体系可排除R-H+以及水分对最终产氢结果的影响。高温存储及高温过充测试后,正极对称电池循环后内部均未检测到H2,因此碳酸酯解离成H∙产氢机理不成立。In this work,gas chromatography(GC)and rechargeable symmetrical lithium-ion batteries were used to explore the causes of H2 generation in NCM lithium-ion batteries(LIBs).In addition to determining whether H2 is produced by the reduction of trace water in the battery,this paper explores whether the H2 generation mechanisms for NCM LIBs are best described as arising from the proton electrolyte oxide(R-H+)or carbonate dissociation into H•.Considering that R-H+deposited on the negative electrode is the related product between the positive and negative electrodes,the graphite/graphite negative symmetrical cell(NSC),the NCM/NCM(LiNi0.6Co0.2Mn0.2O2 is defined as NCM)positive symmetrical cell(PSC),and graphite/NCM pouch cell(PC)with charge and discharge capacity were prepared.After a room temperature cycling test and an overcharge test,the GC results indicated that H2 was produced in the soft package full cell and the negative symmetrical battery,but not in the positive symmetrical battery.This result supports the R-H+mechanism,where H2 is produced by the reduction of the R-H+deposited on the negative electrode,so in the positive symmetrical cell,no H2 is produced.In order to eliminate any interfering signal of H2 produced by the reduction of trace water in the battery,the positive symmetrical battery without H2 generation after cycles was selected.After adding trace water to the system,H2 was indeed detected in the GC results.Therefore,H2 production from trace moisture in the original cells can be ignored.Finally,the mechanism of H2 production by the dissociation of carbonate to H•was tested using the positive symmetric cell.The influence of R-H+and water on the final H2 production can be ignored according to the previous experimental results.After a high temperature storage and a high temperature overcharge test,no H2 was detected in the cathode symmetry battery after cycling,so the mechanism of H2 production by dissociation of carbonate to H•is not the active mechanism.

关 键 词：气相色谱 对称电池 H2 R-H^+ H^· 

分 类 号：TM911[电气工程—电力电子与电力传动]