Characterization of electrospun PVdF fiber-based polymer electrolytes
Characterization of electrospun PVdF fiber-based polymer electrolytes
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DOI：
10.1021/cm060223
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发表时间：
2007-01-09
影响因子：
8.6
通讯作者：
Cairns, Elton J.
中科院分区：
文献类型：
--
作者：
Choi, Sung Won;Kim, Jeong Rae;Cairns, Elton J.
采用静电纺丝技术制备了具有三维网络结构、高孔隙率、大电解质溶液吸收率和足够机械性能的PVdF纤维基膜。它们的物理性质，包括表面形态、平均纤维直径、孔径和电解质溶液吸收，强烈地依赖于用于静电纺丝的聚合物溶液的组成。从X-射线衍射和FT-拉曼光谱数据，我们发现PVdF膜具有II型（α型）和III型（γ型）的混合晶体结构。通过将多孔PVdF膜浸入1M LiPF6电解质溶液中来制备电纺PVdF纤维基聚合物电解质。基于PVdF纤维基聚合物电解质的FT-Raman数据，结果表明碳酸亚乙酯分子主要参与锂盐的溶剂化。此外，除碳酸二乙酯外，这些脂肪族碳酸酯分子与PVdF链强烈相互作用。聚合物电解质在室温下表现出高达1.0 × 10（-3）S/cm的高离子电导率，以及0.0至4.5 V vs Li/Li+的宽电化学稳定窗口。PVdF纤维基聚合物电解质的离子电导率取决于孔内的1 M LiPF6电解质溶液的物理化学性质，而它们的电化学性质通过PVdF链和脂肪族碳酸酯分子之间的相互作用而增强。因此，具有PVdF纤维基聚合物电解质的原型电池根据IM LiPF 6电解质溶液的溶剂组成和C-速率显示出一系列不同的充电/放电性质。此外，循环性能取决于电纺PVdF纤维基聚合物电解质的电化学和光谱性质。
Porous PVdF fiber-based membranes with a three-dimensional network structure, high porosity, large electrolyte solution uptake, and adequate mechanical properties were prepared by an electrospinning technique using various mixed-solvent compositions with poly(vinylidene fluoride) (PVdF). Their physical properties, including surface morphology, average fiber diameter, pore size, and electrolyte solution uptake, strongly depended on the composition of the polymer solution used for electrospinning. From X-ray diffraction and FT-Raman data, we found the PVdF membranes to have mixed-crystal structure sof Form II (alpha-type) and Form III (gamma-type). Electrospun PVdF fiber-based polymer electrolytes were prepared by immersing porous PVdF membranes into 1 M LiPF6 electrolyte solutions. On the basis of FT-Raman data of the PVdF fiber-based polymer electrolytes, it was shown that ethylene carbonate molecules mainly participated in the solvation of the lithium salt. Moreover, with the exception of diethyl carbonate, these aliphatic carbonate molecules strongly interacted with the PVdF chain. The polymer electrolytes exhibited high ionic conductivities up to 1.0 x 10(-3) S/cm at room temperature, and wide electrochemical stability windows of 0.0 to 4.5 V vs Li/Li+. The ionic conductivity of the PVdF fiber-based polymer electrolytes depended on the physicochemical properties of the 1 M LiPF6 electrolyte solution inside the pores, whereas their electrochemical properties were enhanced by the interaction between the PVdF chain and the aliphatic carbonate molecules. Thus, prototype cells with PVdF fiber-based polymer electrolytes showed a range of different charge/discharge properties according to the solvent composition of the 1 M LiPF6 electrolyte solutions and the C-rate. In addition, the cycling performances depended on the electrochemical and spectroscopic properties of the electrospun PVdF fiber-based polymer electrolytes.