Tian Yuan, Pei Nanbiao, Xue Jiyuan, Wang Jinzhi, Zhang Haitang, Tu Wenbin, Sun Xin, Zhang Peng, Qiao Yu, Sun Shi-Gang
State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 PR China
Discipline of Intelligent Instrument and Equipment, College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 PR China.
Chem Sci. 2025 Aug 19. doi: 10.1039/d5sc04442a.
Poly(ethylene oxide) (PEO)-based polymer electrolytes have attracted considerable attention for solid-state batteries due to their excellent processability and interfacial compatibility. However, the incomplete understanding of decomposition byproducts fundamentally hinders the elucidation of degradation mechanisms and the rational design of stable interfaces. In this work, we employed online mass spectrometry and gas chromatography-mass spectrometry (GC-MS) methods to investigate the interfacial reactions between PEO-based electrolytes and activated electrodes ( lithium metal anode and LiCoO cathode), as well as the decomposition products of PEO under both electrochemical cycling and thermal runaway conditions. In addition to permanent gases (H, CO, O, ), we successfully tracked the dynamic evolution of several cyclic ether compounds (1,4-dioxane, ethylene oxide, dioxolane, and 2-methyl-1,3-dioxolane) with voltage-/temperature-dependence, by exploiting the efficient gas chromatographic separation capability of GC-MS for complex gaseous products. These findings provide critical insights into the dynamic degradation behavior of PEO-based electrolytes, advancing our understanding of their decomposition pathways under varying operational conditions and establishing a material design framework for the rational development of next-generation polymer electrolytes.
基于聚环氧乙烷（PEO）的聚合物电解质因其出色的加工性能和界面兼容性，在固态电池领域备受关注。然而，对分解副产物的认识不足，从根本上阻碍了对降解机制的阐释以及稳定界面的合理设计。在这项工作中，我们采用在线质谱和气相色谱 - 质谱联用（GC - MS）方法，研究了基于PEO的电解质与活性电极（锂金属阳极和LiCoO阴极）之间的界面反应，以及PEO在电化学循环和热失控条件下的分解产物。除了永久性气体（H、CO、O等），我们利用GC - MS对复杂气态产物的高效气相色谱分离能力，成功追踪了几种环醚化合物（1,4 - 二氧六环、环氧乙烷、二氧戊环和2 - 甲基 - 1,3 - 二氧戊环）随电压/温度变化的动态演变。这些发现为基于PEO的电解质的动态降解行为提供了关键见解，加深了我们对其在不同运行条件下分解途径的理解，并为下一代聚合物电解质的合理开发建立了材料设计框架。
