The interfacial evolution between polycarbonate-based polymer electrolyte and Li-metal anode
The interfacial evolution between polycarbonate-based polymer electrolyte and Li-metal anode
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DOI：
10.1016/j.jpowsour.2018.07.008
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发表时间：
2018-09-01
影响因子：
9.2
通讯作者：
Cui, Guanglei
中科院分区：
文献类型：
--
作者：
Wang, Chen;Zhang, Huanrui;Cui, Guanglei
固体聚合物电解质被认为是解决高能锂电池中易燃液体有机碳酸酯溶剂安全性问题的关键材料之一，但其室温离子电导率低，严重制约了其发展和应用。最近，已报道脂族聚碳酸酯基电解质在环境温度下具有高离子电导率。本文以聚碳酸亚丙酯为模型，研究了聚碳酸酯基聚合物电解质高离子电导率的来源。我们的研究结果表明，聚碳酸亚丙酯降解到小分子段时，接触锂金属阳极。解聚产物可渗透界面并溶胀电解质以形成非晶态，从而降低界面电阻和体电阻。作为电解质的支架，纤维素可以通过物理阻碍将该反应限制在界面处。羟基单元还可以淬灭锂醇盐中间体以抑制进一步降解，保证系统的安全性。该研究对聚合物电解质与锂金属阳极之间界面的组成、反应和演变有了深入的了解，为研究室温固态锂金属电池的界面结构提供了新的思路。
Solid polymer electrolyte is strongly considered to be one of the key materials to solve safety problem of high energy lithium batteries caused by flammable liquid organic carbonate solvent, while the development and application of solid polymer electrolytes are seriously restricted by the low ambient temperature ionic conductivity. Recently, aliphatic polycarbonate-based electrolytes have been reported to possess high ionic conductivity at ambient temperature. Herein we choose poly (propylene carbonate) as a model to investigate the origin of the high ionic conductivity of polycarbonate-based polymer electrolytes. Our results prove that poly (propylene carbonate) degrades to micromolecular segments when contacts with Li-metal anode. The depolymerization products can infiltrate the interface and swell the electrolyte to develop the amorphous state so as to reduce both interfacial and bulk resistance. As scaffold of the electrolyte, cellulose can limit this reaction at the interface by physical obstruction. The hydroxyl units can also quench the lithium alkoxide intermediate to suppress further degradation, guaranteeing the security of the system. This study provides a profound understanding of the composition, reaction and evolution of the interface between polymer electrolyte and Li-metal anode, which sheds new light on the interface construction of ambient-temperature solid-state lithium metal batteries.