PVDF/Graphene Composite Nanoporous Membranes for Vanadium Flow Batteries
PVDF/Graphene Composite Nanoporous Membranes for Vanadium Flow Batteries
复制标题
DOI：
10.3390/membranes9070089
复制
发表时间：
2019-07-01
期刊：
影响因子：
4.2
通讯作者：
Wang, Baoguo
中科院分区：
文献类型：
--
作者：
Lai, Yiming;Wan, Lei;Wang, Baoguo
开发化学稳定的高导电膜是提高全钒液流电池（VFB）性能的最重要问题之一。在此，通过操纵结晶过程可以轻松地制备聚偏二氟乙烯（PVDF）/石墨烯复合纳米多孔膜。石墨烯用于增强膜的选择性和电导率。在膜的纳米级通道中，石墨烯纳米片减少了晶粒之间的孔径，从而由于尺寸排阻效应而抑制了钒离子的穿过。此外，石墨烯上的氧基团提高了表面亲水性，并与PVDF聚合物链形成氢键，有利于质子传输。石墨烯负载量为 0.15 wt% 的复合膜显示出 38.2 的选择性和 37.1 mS/cm 的电导率。单电池的库伦效率为94.7%，电压效率为88.5%，能量效率为83.8%，比原始PVDF膜高13%。该复合膜在100次充放电循环中表现出优异的稳定性。所有这些结果表明PVDF/石墨烯复合膜是VFB应用的有希望的候选者。
The development of chemically stable and high conductive membranes is one of the most important issues to improve the performance of vanadium flow batteries (VFBs). Herein, poly(vinylidene fluoride) (PVDF)/graphene composite nanoporous membranes were easily fabricated by manipulating crystallization processes. The graphene was used to enhance membrane selectivity and conductivity. In the nanoscale channels of the membranes, the graphene nanosheets reduced the apertures among the crystal grains, thus restraining vanadium ions crossover due to the size exclusion effect. Moreover, the oxygen groups on the graphene improved the surface hydrophilicity and formed hydrogen bonds with the PVDF polymer chains, which facilitated the proton transport. The composite membranes, with a 0.15 wt % graphene loading, showed a selectivity of 38.2 and conductivity of 37.1 mS/cm. The single cell exhibited a coulomb efficiency of 94.7%, a voltage efficiency of 88.5%, and an energy efficiency of 83.8%, which was 13% higher than that of the pristine PVDF membranes. The composite membranes showed excellent stability during 100 charge-discharge cycles. All these results indicate that the PVDF/graphene composite membrane is a promising candidate for VFB applications.