具有优异热稳定性的锂离子电池超亲电解液隔膜的制备及性能研究

项目名称： 具有优异热稳定性的锂离子电池超亲电解液隔膜的制备及性能研究

项目编号： No.51503212

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 李步成

作者单位： 中国科学院兰州化学物理研究所

项目金额： 20万元

中文摘要： 隔膜作为锂离子电池的核心材料之一，直接影响着电池的能量密度、功率密度、循环寿命和安全性。针对目前聚烯烃类隔膜存在电解液润湿性差和热稳定性差的问题，本项目拟通过多巴胺改性聚乙烯（PE）隔膜和化学气相沉积有机硅烷聚合物纳米纤维（SNFs），调控PE隔膜的表面化学组成和形貌，构筑具有三明治结构的新型超亲电解液SNFs改性PE隔膜。通过多种分析测试手段，结合Material Studio计算模拟，研究溶有六氟磷酸锂的碳酸乙烯酯、碳酸二乙酯基电解液对SNFs改性PE隔膜的润湿性，分析隔膜的表面化学组成和形貌对润湿性和热稳定性的影响，建立构-效关系；通过组装磷酸铁锂/中间相炭微球实验电池，研究超亲电解液SNFs改性PE隔膜对锂离子电池综合性能的影响，揭示超亲电解液隔膜对提高锂离子电池性能的作用机制。通过本项目研究，为研究和设计高性能锂离子电池隔膜材料提供实验基础和科学依据。

中文关键词： 锂离子电池；隔膜；电解液；润湿性；有机硅烷聚合物纳米纤维

英文摘要： Separator, as one of the key components of lithium ion battery, has great influences on the battery performance including energy density, power density, cycle life and safety. The low wettability by electrolytes of lithium ion battery and the poor thermal stability are the main problems of the existing polyolefin separators. Here we proposed to prepare novel superwetting polyethylene (PE) separators for electrolytes with a sandwich structure by modification with polydopamine, and then coating with silicone nanofilaments (SNFs) via chemical vapor deposition. The surface chemical composition and morphology of PE separators can be controlled by the polydopamine layer and the SNFs layer. The wettability of the SNFs-coated PE separators by the electrolytes composed of ethylene carbonate, diethyl carbonate and LiPF6 will be studied in detail using a variety of analytical techniques and the numerical simulation of Material Studio. In addition, the effects of surface chemical composition and morphology on the wettability and the thermal stability of the SNFs-coated PE separators will be investigated, which is helpful to reveal the structure-activity relationship. Moreover, the influences of the superwetting SNFs-coated PE separators on the comprehensive performance of lithium ion battery will be evaluated by assembling the LiFePO4/MCMB experimental cells, which is helpful to reveal the mechanism for the improvement of the battery performance. This project will set the experimental basis and scientific evidence for the research and design of novel separators of high-performance lithium ion battery.

英文关键词： Lithium ion battery;Separator;Electrolyte;Wettability;Silicone Nanofilaments