物理化学学报 >> 2011, Vol. 27 >> Issue (01): 78-84.doi: 10.3866/PKU.WHXB20110112

电化学和新能源 上一篇    下一篇

P(VdF-HFP)-基离子液体复合聚合物电解质的阴极稳定性及热稳定性

崔闻宇, 安茂忠, 杨培霞, 张锦秋   

  1. 哈尔滨工业大学化工学院, 哈尔滨150001
  • 收稿日期:2010-09-20 修回日期:2010-10-28 发布日期:2010-12-31
  • 通讯作者: 安茂忠 E-mail:mzan@hit.edu.cn
  • 基金资助:

    黑龙江省自然科学基金(B2007-05)资助项目

Cathodic and Thermal Stabilities of the P(VdF-HFP)-Based Ionic Liquid Composite Polymer Electrolyte

CUI Wen-Yu, AN Mao-Zhong, YANG Pei-Xia, ZHANG Jin-Qiu   

  1. School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, P. R. China
  • Received:2010-09-20 Revised:2010-10-28 Published:2010-12-31
  • Contact: AN Mao-Zhong E-mail:mzan@hit.edu.cn
  • Supported by:

    The project was supported by the Natural Science Foundation of Heilongjiang Province, China (B2007-05).

摘要:

以聚偏氟乙烯-六氟丙烯P(VdF-HFP)聚合物为基体, 制备了含离子液体1-甲基-3-乙基咪唑六氟磷酸盐(EMIPF6)、用于锂离子电池的离子液体复合聚合物电解质[P(VdF-HFP)/LiPF6/EMIPF6/EC(碳酸乙烯酯)-PC(碳酸丙烯酯)]. 采用热重分析法以及燃烧实验测试了复合聚合物电解质的热稳定性. 离子电导率测试表明, 离子液体的存在显著改善了复合聚合物电解质的离子传输; 循环伏安测试表明, 添加剂EC和PC的加入提高了复合电解质的阴极稳定性, 制得的离子液体复合聚合物电解质在0.3-4.3 V 电压范围内稳定存在. Li4Ti5O12 和LiCoO2为电极材料、P(VdF-HFP)/LiPF6/EMIPF6/EC-PC 为电解质的半电池表现出优良的循环性能, 0.1C充放电倍率下, Li/LiCoO2和Li/Li4Ti5O12半电池的可逆容量分别为130和144 mAh·g-1. 但EC、PC在一定程度上降低了离子液体复合聚合物电解质的热稳定性.

关键词: 锂离子电池, 离子液体, 复合聚合物电解质, 阴极稳定性, 热稳定性

Abstract:

We report on a composite polymer electrolyte containing the ionic liquid 1-ethyl-3- methylimidazolium hexafluorophosphate (EMIPF6). This composite polymer electrolyte is based on the poly(vinylidene fluoride-co-hexafluoropropylene) (P(VdF-HFP)) polymer matrix and is a potential electrolyte for use in lithium ion batteries. The ionic conductivity of the composite polymer electrolyte was measured by electrochemical impedance spectroscopy (EIS). Linear sweep voltammetry (LSV) was performed to investigate the electrochemical stability window of the polymer electrolyte. The thermal properties for the composite polymer electrolyte were also characterized by thermogravimetry (TG) and by a flammability test. The results show that the presence of the EMIPF6 ionic liquid increases the ion transport properties greatly but a better cathodic stability is only obtained by the addition of organic additives such as ethylene carbonate-propylene carbonate (EC-PC), which extends the cathodic stability to 0.3 V. This corresponds to an electrochemical stability window of 0.3-4.3 V. The selected Li4Ti5O12 anode and LiCoO2 cathode materials exhibit acceptable electrochemical performance in combination with the prepared P(VdF-HFP)/ LiPF6/EMIPF6/EC-PC composite polymer electrolyte. At a charge-discharge rate of 0.1C, Li/LiCoO2 and Li/ Li4Ti5O12 have reversible capacities of 130 and 144 mAh·g-1, respectively. However, the corresponding thermal performance is suppressed because of the presence of organic additives.

Key words: Lithium ion battery, Ionic liquid, Composite polymer electrolyte, Cathodic stability, Thermal stability

MSC2000: 

  • O646