Poly(Vinylidene Difluoride) Soft Dendritic Colloids as Li-Ion Battery Separators
Poly(Vinylidene Difluoride) Soft Dendritic Colloids as Li-Ion Battery Separators
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DOI：
10.1149/1945-7111/abdfa7
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发表时间：
2021-01
影响因子：
3.9
通讯作者：
Salvatore Luiso;Austin H. Williams;Michael J. Petrecca;Sangchul Roh;O. Velev;P. Fedkiw
中科院分区：
文献类型：
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作者：
Salvatore Luiso;Austin H. Williams;Michael J. Petrecca;Sangchul Roh;O. Velev;P. Fedkiw
作为锂离子电池(Lib)微孔膜分离器(通常由聚烯烃组成)的替代品，其他材料和分离器形态可能会提高电池性能。在这里，我们提出了一种新型的LiB分离器，它由聚偏二氟乙烯(PVDF)为基础的高度支化的胶体聚合物颗粒组成，称为软树枝状胶体，由剪切驱动的聚合物在湍流的非溶剂流中沉淀后过滤产生。我们发现，所得到的PVDF颗粒的形态可能从纤维状树枝状胶体到薄且高度多孔的片状颗粒。聚偏氟乙烯的使用导致了低的热收缩(90℃时为5%)和高的抗拉强度(1000psi时偏移量为0.7%)，而高孔隙率(高达80%)和高颗粒比表面积导致了高电导率(1.2ms cm−1)和电解液吸收率(325%)，以及良好的电池容量(Li/LiCoO2电池中的112mAhg−1)，在50次循环后损失了<；10%。由于剪切驱动过滤沉淀法是一种简便、通用的方法来制备新型聚合物锂离子电池隔膜，软树枝状胶体有望成为下一代电池隔膜的候选材料。
As an alternative to Li-ion battery (LIB) microporous membrane separators that are typically comprised of polyolefins, other materials and separator morphologies may yield increased cell performance. Here, we present a new class of LIB separators comprising poly (vinylidene difluoride)(PVDF)-based and highly branched, colloidal polymer particulates, called soft dendritic colloids, that are produced by shear-driven polymer precipitation within a turbulent nonsolvent flow followed by filtration. We show the morphology of the resulting PVDF particulates may be varied from fibrous dendritic colloids to thin and highly porous sheet-like particles. The use of PVDF leads to low thermal shrinkage (5% at 90 C) and high tensile strength (< 0.7% offset at 1000 psi), while the high porosity (up to 80%) and high particle surface area are responsible for high conductivity (1.2 mS cm− 1) and electrolyte uptake (325%), and good cell capacity (112 mAh g− 1 in Li/LiCoO 2 cell) with< 10% loss after 50 cycles. Because shear-driven precipitation with filtration is a facile and versatile process to make a new class of polymeric LIB separators, soft dendritic colloids are promising candidates as separators for next-generation batteries.