Theoretical insight into oxidative decomposition of propylene carbonate in the lithium ion battery.
Theoretical insight into oxidative decomposition of propylene carbonate in the lithium ion battery.
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DOI：
10.1021/jp810279h
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发表时间：
2009-03
期刊：
影响因子：
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通讯作者：
L. Xing;Chaoyang Wang;Weishan Li;Mengqing Xu;Xuliang Meng;Shaofei Zhao
中科院分区：
文献类型：
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作者：
L. Xing;Chaoyang Wang;Weishan Li;Mengqing Xu;Xuliang Meng;Shaofei Zhao
采用密度泛函理论（DFT）方法，在B3 LYP/6-311++G（d）水平上研究了锂离子电池中碳酸丙烯酯（PC）在气相和溶剂中的氧化分解机理.计算结果表明，PC首先在阴极上被氧化成自由基阳离子中间体PC（*+），然后通过三条途径分解，生成二氧化碳、CO（2）和自由基阳离子。这些自由基阳离子优选在阳极上还原或通过从PC获得一个电子而还原，形成丙醛、丙酮或相关自由基。自由基通过形成最终产物而终止，包括反式-2-乙基-4-甲基-1，3-二氧戊环、顺式-2-乙基-4-甲基-1，3-二氧戊环和2，5-二甲基-1，4-二氧杂环己烷。在所有产物中，丙酮是最容易形成的。本文中的计算给出了详细的解释，已在文献中报道的实验结果，并澄清中间体环氧丙烷在PC分解中的作用。环氧丙烷是重要的中间体之一。当环氧丙烷形成时，它异构化形成更稳定的产物丙酮。
The detailed oxidative decomposition mechanism of propylene carbonate (PC) in the lithium ion battery is investigated using density functional theory (DFT) at the level of B3LYP/6-311++G(d), both in the gas phase and in solvent. The calculated results indicate that PC is initially oxidized on the cathode to a radical cation intermediate, PC(*+), and then decomposes through three pathways, generating carbon dioxide CO(2) and radical cations. These radical cations prefer to be reduced on the anode or by gaining one electron from PC, forming propanal, acetone, or relevant radicals. The radicals terminate by forming final products, including trans-2-ethyl-4-methyl-1,3-dioxolane, cis-2-ethyl-4-methyl-1,3-dioxolane, and 2,5-dimethyl-1,4-dioxane. Among all the products, acetone is most easily formed. The calculations in this paper give detailed explanations of the experimental findings that have been reported in the literature and clarify the role of intermediate propylene oxide in PC decomposition. Propylene oxide is one of the important intermediates. As propylene oxide is formed, it isomerizes forming a more stabile product, acetone.