Sulfonated poly(ether ether ketone) and sulfonated poly(1,4-phenylene ether ether sulfone) membranes for vanadium redox flow batteries

Abstract

Nafion is a currently used as a proton exchange membrane in vanadium redox flow batteries (VRBs). It is an excellent proton-conducting and fully hydrated membrane, but it is costly. In order to reduce the cost of the membrane used in VRBs and to reduce vanadium permeability across the membrane, sulfonated poly(ether ether ketone) (S-PEEK) and sulfonated poly(1,4-phenylene ether ether sulfone) (S-PPEES) membranes were fabricated and studied as a function of the sulfonation reaction time. The increase in the degree of sulfonation from 46 to 86% induced increases in the water uptake, ion exchange capacity, proton conductivity, and vanadium permeability. The vanadium permeability coefficients of S-PEEK and S-PPEES membranes are in the range of 0-24.95 Â 10 -7 cm 2 min -1 , which are significantly lower than that of Nafion 117, which is 30.84 Â 10 -7 cm 2 min -1 . The proton conductivity of S-PEEK in our study is nine times higher than sulfonated poly(arylene ether ketone) in a previous work and more suitable for using in VRBs.

Sulfonated polyphenylsulfone asymmetric membranes: Effect of coagulation bath (acetic acid‐NaHCO3/isopropanol) on morphology and antifouling properties

“…Modifications such as, carboxylation, chloromethylation, phosphonation followed by sulfonation, and direct sulfonation have shown to impart hydrophilicity and surface charge in polymers . One of the most used chemical modification is the direct sulfonation which consist of an aromatic electrophilic substitution reaction in which a sulfonic acid, SO 3 H, is introduced in the ortho positions of the aromatic ring in place of hydrogen . This process is carried out using sulfonating agents such as chlorosulfonic acid (ClSO 3 H), sulfuric acid (H 2 SO 4 ), sulfur trioxide (SO 3 ), and trimethylsilyl chlorosulfonate, TMSClS (CH 3 ) 3 SiSO 3 Cl .…”

Ion exchange membranes for vanadium redox flow batteries

“…Compared with the pristine SPEEK, VRB assembled with the composite membrane presents longer retention time (27 vs. 14 h) at OCV above 1.3 V. It indicates that SPEEK/PTFE composite membrane has lower vanadium ion permeability than the SPEEK one. In addition, VRB from PEEK/PTFE composite membrane shows higher VE (89.6 ± 1 % vs. 86.7 ± 1 %) and EE (86.7 ± 1 % vs. 82 ± 1 %) compared with that from Nafion 115 [76].…”

“…In the meanwhile, their self-discharge rates are much slower and they show longer duration time above 1.2 V (80 h vs. 160 h). To increase proton conductivity, sulfonated poly(1,4-phenylene ether ether sulfone) (SPPEES) membranes are fabricated with 98 % sulfuric acid at different reaction time [76]. The hydrophilic domains formed by the hydrophilic sulfonic groups are well interconnected, and protons, water and vanadium ions can transport through.…”

Assessment of high performanceSAPO‐34/S‐PEEKcomposite coatings for adsorption heat pumps

“…Moreover, the S‐PEEK spectrum shows the presence of a new peak at 1248 cm −1 related to asymmetric OSO stretching 36,37 . Furthermore, absorption peaks, not observed in PEEK spectrum, at 1076, 1022, and 705 cm −1 are ascribed to the symmetric OSO, SO bending, and SO stretching of sulfone group, respectively 38,39 …”