SPEEK/Graphene oxide nanocomposite membranes with superior cyclability for highly efficient vanadium redox flow battery

Abstract

A series of novel composite membranes, based on sulfonated poly(ether ether ketone) (SPEEK) with various graphene oxide (GO) loadings, were employed and investigated in vanadium redox flow battery (VRFB) for the first time. The scanning electron microscopy images of the composite membranes revealed the uniform dispersion of GO nanosheets in the polymer matrix due to the interaction between GO and SPEEK, as confirmed by Fourier transform infrared spectra. The mechanical and thermal parameters of the composite membranes increased, while the VO 2+ permeability decreased with increasing GO content.Random embedding of GO nanosheets in the membranes can serve as effective barriers to block the transport of vanadium ion, resulting in a significant decrease of vanadium ion permeability. The VRFB assembled with the composite membrane exhibited highly improved cell parameters and strikingly long cycling stability compared with commercial Nafion 117 membrane. With the protection of porous PTFE substrate, the pore-filling SPEEK/GO composite membrane based on VRFB ran for 1200 cycles with relatively low capacity decline.

Highly branched sulfonated poly(fluorenyl ether ketone sulfone)s membrane for energy efficient vanadium redox flow battery

“…The typical absorption peaks of HSPAEK can be assigned to carbonyl stretching at 1647 cm À1 , skeletal in-plane vibration of phenyl rings at 1481 cm À1 , asymmetric and symmetric stretching of O]S]O at 1240 and 1079 cm À1 . The peaks at 1450e1650 cm À1 can be ascribed to the benzene skeleton vibration of the polysulfone backbone [27,50,51].…”

“…The VRFB single cell configuration was the same as reported previously [27,49]. The membrane (70 mm  70 mm) was sandwiched between two thermal activated graphite felt electrodes (50 mm  50 mm  5 mm).…”

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.…”

Toward improved mechanical strength, oxidative stability and proton conductivity of an aligned quadratic hybrid (SPEEK/FPAPB/Fe3O4-FGO) membrane for application in high temperature and low humidity fuel cells

“…4 40,43,44 Compared to SP, the hybrid membranes reveal a new low intensity peak at 2784 cm À1 , which is attributed to C-F stretching of aromatic rings in FPAPB. The slight peak shis (especially -OH peaks) in SPF and SPFSGF-5 The crystalline faces of GO, FGO and Fe 3 O 4 -FGO were analysed by using XRD, and the corresponding patterns are presented in Fig.…”