SPPEK/TPA composite membrane as a separator of vanadium redox flow battery

Low vanadium ion permeabilities of sulfonated poly(phthalazinone ether ketone)s provide high efficiency and stability for vanadium redox flow batteries

“…This can be due to the degradation of sulfonic acid groups in VO 2 þ solution. In testing the stability after 30 days of soaking, the weight losses of SPPEK-P-70, SPPEK-P-80 and SPPEK-P-90 membranes are lower than that of SPPEK-TPA membranes (3.87%) at the same conditions [30], and also lower than that of sulfonated poly(ether ether ketone)/polyacrylonitrile acid blend membrane (4.0%) after soaking for two weeks [31]. Even after 60 days of soaking, the weight losses of SPPEK-P-70 and SPPEK-P-80 are still lower than 4.0%.…”

Poly(phenyl sulfone) anion exchange membranes with pyridinium groups for vanadium redox flow battery applications

“…1), a new peak at 4.64 ppm was assigned to the methylene protons in the chloromethyl groups [34]. As mentioned in the experimental part, degree of substitution (DS) of chloromethylated poly(phenyl sulfone) was calculated from 1 H NMR spectroscopy by taking the integral ratio of eCH 2 Cl (H(2)) at 4.64 ppm to the poly(phenyl sulfone) backbone protons at 7.90 ppm (H (11,12,13,14)) which were intact during the chloromethylation reaction, and the calculation equation was shown as following:…”

“…where A 2 was the integration value of H(2), A 11,12,13,14 was the integration value of H (11,12,13,14), respectively.…”

Synthesis and properties of branched sulfonated polyimides for membranes in vanadium redox flow battery application

“…Consequently, development of more stable non-fluorinated proton conductive membranes is an ongoing effort undertaken by many researchers. Commonly-used strategies to improve the stability of non-fluorinated proton conductive membranes are as the following: On one hand, organic-inorganic composite membranes such as sulfonated poly (ether ether ketone)/graphene oxide (SPEEK/GO) [13], sulfonated poly(phthalazinone ether ketone)/tungstophosphoric acid (SPPEK/TPA) [14], sulfonated poly(arylene ether sulfone)/laponite-SO 3 H (SPEAS/SLa) [15] and sulfonated polyimide/s-MoS 2 (SPI/s-MoS 2 ) membranes [16] were prepared by adding inorganic fillers or segments into non-fluorinated polymers; On another hand, the monomers used to synthesize non-fluorinated polymers were designed and optimized, in order that the stability of nonfluorinated polymers themselves can be improved. Our earlier work [17] verified the feasibility of the latter strategy, which spurs us to do more relative work about preparation of non-fluorinated polymer membranes made of more stable monomers.…”