Swelling and softening of lithium-ion battery separators in electrolyte solvents
Swelling and softening of lithium-ion battery separators in electrolyte solvents
复制标题
DOI：
10.1016/j.jpowsour.2015.06.028
复制
发表时间：
2015-10-30
影响因子：
9.2
通讯作者：
Arnold, Craig B.
中科院分区：
文献类型：
--
作者：
Gor, Gennady Y.;Cannarella, John;Arnold, Craig B.
非活性聚合物组分（例如隔膜和粘合剂）的机械稳定性可以在锂离子电池的长期性能中发挥重要作用。在这里，我们调查电解质溶剂对聚丙烯电池隔膜的机械性能的影响，通过实验测量的厚度和弹性模量的隔膜样品浸泡在不同的溶剂环境。我们发现，某些电解质溶剂，如碳酸二甲酯，碳酸二乙酯，和乙酸乙酯导致明显软化的隔膜。然而，在其他溶剂环境中，如碳酸丙烯酯和乙腈，隔膜保持干燥材料的机械性能。我们发现，机械性能的降低可以归因于聚合物溶胀，并解释这些观察的背景下的希尔德布兰德溶解度和Flory-Huggins相互作用参数。溶解度/相互作用参数的分析提供了一个简单的方法来预测在溶剂环境中的聚合物隔膜的原位机械行为。本文讨论的关系可用于筛选和鉴定机械稳定的聚合物和电解质溶剂对，以用于设计用于长寿命的锂离子电池。(C)2015 Elsevier B. V.版权所有。
The mechanical stability of inactive polymeric components (e.g. separator and binder) can play an important role in the long term performance of lithium-ion batteries. Here we investigate the effects of electrolyte solvents on the mechanical properties of a polypropylene battery separator through experimental measurements of thickness and elastic modulus of separator samples immersed in different solvent environments. We find that certain electrolyte solvents such as dimethyl carbonate, diethyl carbonate, and ethyl acetate cause noticeable softening of the separator. However, in other solvent environments such as propylene carbonate and acetonitrile, the separator retains the mechanical properties of a dry material. We show that the mechanical property reduction can be attributed to polymer swelling and explain these observations in the context of the Hildebrand solubility and Flory-Huggins interaction parameters. The solubility/interaction parameter analysis provides a straightforward method for predicting the in situ mechanical behavior of polymer separators in solvent environments. The relationships discussed herein can be used to screen and identify mechanically-stable polymer and electrolyte solvent pairs for use in lithium-ion batteries designed for long life. (C) 2015 Elsevier B.V. All rights reserved.