Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5149559 | Journal of Power Sources | 2017 | 13 Pages |
Abstract
A novel branched side-chain-type sulfonated polyimide (6F-s-bSPI) membrane with accessible branching agents of melamine, hydrophobic trifluoromethyl groups (CF3), and flexible sulfoalkyl pendants is prepared by a high-temperature polycondensation and post-sulfonation method for use in vanadium redox flow batteries (VRFBs). The chemical structure of the 6F-s-bSPI membrane is confirmed by ATR-FTIR and 1H NMR spectra. The physico-chemical properties of the as-prepared 6F-s-bSPI membrane are systematically investigated and found to be strongly related to the specially designed structure. The 6F-s-bSPI membrane offers a reduced cost and possesses a significantly lowered vanadium ion permeability (1.18Â ÃÂ 10â7Â cm2Â minâ1) compared to the linear SPI (2.25Â ÃÂ 10â7Â cm2Â minâ1) and commercial Nafion 115 (1.36Â ÃÂ 10â6Â cm2Â minâ1) membranes, prolonging the self-discharge duration of the VRFBs. In addition, the VRFB assembled with a 6F-s-bSPI membrane shows higher coulombic (98.3%-99.7%) and energy efficiencies (88.4%-66.12%) than that with a SPI or Nafion 115 membrane under current densities ranging from 20 to 100Â mAÂ cmâ2. Moreover, the VRFB with a 6F-s-bSPI membrane delivers a stable cycling performance over 100 cycles with no decline in coulombic and energy efficiencies. These results show that the branched side-chain-type structure is a promising design to prepare excellent proton conductive membranes.
Related Topics
Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Jinchao Li, Suqin Liu, Zhen He, Zhi Zhou,