摘要
研究了LiCoO_(2)正极和氧化亚硅/石墨复合负极(LiCoO_(2)-SiO/石墨)软包锂离子电池体系(LIBs)循环衰减机理,通过循环过程中电化学阻抗(EIS)、增量容量分析(ICA)、正负极形貌等分析了循环的影响因素。结果表明,硅基负极材料在完全嵌锂状态下的体积膨胀不仅会导致SiO负极的颗粒破碎,与电解液的副反应加剧,其膨胀应力还会造成电极的导电网络和粘结剂网络的破损,从而导致正负极活性物质利用率降低,降低SiO负极材料的循环性能。此外,SiO负极的充放电电压平台较高,与石墨材料复合使用时,容易造成电池正极的过充和放电容量损失,正极过充会加剧正极材料结构破裂。而随着循环的进行,过充程度和放电容量损失会愈发严重,加速电池循环性能衰减。
The cycling decay mechanism of pouch lithium-ion batteries(LIBs)with LiCoO_(2) cathode and SiO/graphite composite anode was studied.The influencing factors of cycling were analyzed by electrochemical impedance spectroscopy(EIS),incremental capacity analysis(ICA),electrode morphology characterizations during cycling.The results show that the expansion of Si based anode under lithiation leads to particle pulverization and extra side reactions with the electrolyte.The consequent expansion stress can destroy the conductive network and binder network,resulting in the loss of utilization rate of active substances and impairing the cycle performance of SiO anode.In addition,the voltage platform of SiO anode is relatively high.The composite anode of SiO/graphite tends to cause the overcharge of cathode and the loss of discharge capacity.The overcharge of cathode exacerbates the breakdown of cathode material.As the cycle process continues,the overcharge and discharge capacity loss intensify,accelerating the deterioration of cycle performance.
作者
周江
孟繁慧
朱莎
甄会娟
黄铃
ZHOU Jiang;MENG Fanhui;ZHU Sha;ZHEN Huijuan;HUANG Ling(Tianjin Lishen Battery Joint-Stock Co.,Ltd.,Tianjin 300384,China)
出处
《电源技术》
CAS
北大核心
2022年第2期169-172,共4页
Chinese Journal of Power Sources
基金
天津市自然科学基金(20JCYBJC00690)。
