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The understating of hydrated proton activity and its dynamics inside the ion exchange channel of proton exchange membranes (PEMs) are one of the basic need to develop quality membranes for desalination and energy applications. In this work, sulfonated polyethersulfone (SPES), hybrid Silica-SPES and phosphorylated hybrid Silica-SPES composite PEMs are prepared; and membrane properties are characterized with appropriate analytical tools. The enhanced conductivity is described effectively with 1H spin-lattice (T 1), spin-spin (T 2) relaxation and diffusion weighted imaging and their corresponding value determined by magnetic resonance imaging (MRI) technique. This study gives useful insight on variation in the interactions and dynamics of hydrated protons confining inside the membrane channel with the incorporation of silica and its further phosphorylation. Obtained spin-lattice (T 1), spin-spin (T 2) relaxation and diffusion results relate that silica and phosphorylation have facilitated the formation more hurdle free organized pathway for proton conduction. • Enhanced proton conductivity in phosphorylated hybrid silica-SPES compare to SPES. • T 1 , T 2 relate fall in Proton-channel interaction, better hydrated protons interlinking. • Better proton hopping interlinking pathway causing to enhance proton conductivity. [ABSTRACT FROM AUTHOR]

Proton exchange membrane is a basic element for any redox flow battery. Nafion is the only commercial available proton exchange membrane used in different electro-chemical energy systems. High cost restrict it's used for energy generation devices. In present work, we synthesised styrene divinylbenzene based composite proton exchange membranes (PEMs) with varying sulfonated graphene oxide (sGO) content for redox flow battery (RFB). Synthesized copolymer PEMs were analyzed in terms of their chemical structure with the help of FT-IR spectroscopy to confirm desired functional groups at appropriate position. Electrochemical characterization was performed in terms proton-exchange capacity, protonic conductivity and water uptake. Membrane shows adequate proton exchange capacity with good proton conductivity. Vanadium ion permeability was also tested for the prepared membrane to assess capability for vanadium redox flow battery (VRFB) in contrast with commercially available Nafion 117 PEM. Higher VO+2 ion cross-over resistance was found for CEM-4 with 7.17 × 10−7 cm2 min−1 permeability, which is about half of the CEM-1. Further CEM-4 was also evaluated for charging-discharging phenomenon for single cell VRFB. The values of columbic, voltage and energy efficiency for VRFB confirms prepared membrane as a good candidate for redox flow battery. Composite PEM also shows better mechanical and thermal stability. Results indicates that synthesized composite membrane can be used in vanadium redox flow battery. Image 1 • Composite PEM shows the better performance. • Sulfonated graphene oxide may be the unique material for PEM. • Composite membranes are mechanically stable in electro-chemical environment. [ABSTRACT FROM AUTHOR]

The present investigation reports one-pot synthetic approach to develop cation exchange membranes (CEMs) via free radical polymerization which avoids the post functionalization step that involves use of hazardous chemicals. The CEM is composed of sodium styrene sulfonate (StSO3Na), methyl methacrylate, divinyl benzene, and polyvinyl chloride which is prepared by varying relative amount of vinyl monomers. The membranes shown improved ion-exchange capacity, water uptake, ionic conductivity, and stabilities (mechanical, chemical, and thermal). Among different CEMs, CEM-1 has shown significantly improved performance with 8.54 × 10−2S.cm−1 proton conductivity and 2.71 meq. g−1 proton exchange capacity. [ABSTRACT FROM AUTHOR]

Nanoporous composite proton exchange membranes of sulfonated poly ether sulfone (SPES) and sulfonated mesoporous silica (S-MCM-41) have been prepared for energy based applications. Various weight % of Sulfonated MCM-41 has been incorporated in SPES matrix. The presence of surface functionalized MCM-41 as inorganic fillers in the SPES matrix, subsequently led to significant enhancement in the proton exchange capacity and proton conductivity of the nanoporous membranes. Nanoporous composite membranes have been subjected to various structural, thermal and mechanical techniques. Further developed membranes have been analyzed, for methanol permeability to evaluate membrane performance for fuel cell application. Methanol permeability of SM-2 is found to be 2.34 × 10 −8  cm 2  s −1 which is very less than SPES revealing the suitability of composite membranes for fuel cell. [ABSTRACT FROM AUTHOR]

For the synthesis of polymer electrolyte membrane (PEM), high ionic conductivity and stability are the key challenge. This paper deals with the preparation of polymer electrolyte membranes based on ionic liquid (IL) functionalized graphene oxide (GO) and sulfonated polyether sulfone (SPES). Using a simple solution casting technique, composite membranes have been prepared possessing good physicochemical properties and mechanical stability. Methanol crossover resistance have been measured across the composite membranes and found to be low for IG- 05 membrane (0.53 × 10 −7 cm 2 s −1 ) with the selectivity of 7.99 × 10 5 . Composite IG- 05 membrane also exhibit high ionic conductivity of 7.27 × 10 −2 S.cm −1 which is around 66% higher than that of SPES membrane. [ABSTRACT FROM AUTHOR]

We report one pot synthesis of Poly (vinylidene difluoride) based proton conducting membranes (PCM) by free radical polymerization instead of post functionalization that uses hazardous sulfonating agents via electrophilic substitution reaction. PCM synthesised by copolymerization reaction among the three monomers viz Poly (vinylidene difluoride), 1-vinylimidazole and styrene sodium sulfonate. The enhancement in proton conductivity, proton exchange capacity and mechanical stability has been recorded by varying the amount of 1-vinyl imidazole and sodium styrene sulfonate alternatively. The membrane shows the enhancement in water uptake with adequate dimensional stability. PVDF-5 PCM shows the better performance among the membranes with 4.82*10 −2 S/cm proton conductivity and 2.19 meq/g proton exchange capacity. Membranes also shows better oxidative stability as well as mechanical stability. [ABSTRACT FROM AUTHOR]

Energy efficient membranes of SGO (Sulfonated Graphene Oxide) into SPES (Sulfonated Polyethersulfone) matrix have been prepared containing different weight content of SGO. Proton conductivity and water retention capacity of membranes increases by increasing SGO while degree of swelling decreases. TEM micrograph shows the uniform distribution of SGO throughout the membrane. SGO-5 membrane shows the maximum proton conductivity (5.8 x 10−2S/cm), which is almost double to the SPES with higher stability. SGO-5 membrane shows 4.73 mole.m−2h−1ionic flux, 0.98 kWhkg−1power consumption and 93.1% current-efficiency for salt removal, which are 62% and 15.2% higher, respectively, while 16% lower power consumption is observed as compared to SPES. [ABSTRACT FROM PUBLISHER]

A successful approach towards enhancement in ion cluster size of sulfonated poly (arylene ether sulfone) (SPAES)-based membranes has been successfully carried out by encapsulating basic pendent branches as side groups. Modified SPAES was synthesized by condensation polymerization followed by bromination with N-bromosuccinamide (NBS) and sulfonation by ring opening reaction. Various molar ratios of branched polyethyleneimine (PEI) were added to the SPAES and the developed polymer was designated as SPAES-x-PEI-y, where x denoted the number of sulfonating acid group per polymer chain and y represents the amount of PEI concentration. Polymer synthesis was characterized by 1H-NMR (Nuclear magnetic resonance) and FT-IR (Fourier-transform infrared spectroscopy) analysis. A cumulative trend involving enhanced proton conductivity of the membranes with an increase in the molar ratio of PEI has been observed, clearly demonstrating the formation of ionic clusters. SPAES-140-PEI-3 membranes show improved proton conductivity of 0.12 Scm−1 at 80 °C. Excellent chemical stability was demonstrated by the polymer with Fenton's test at 80 °C for 24 h without significant loss in proton conductivity, owing to the suitability of the synthesized hybrid membrane for electrochemical application. Moreover, a single cell degradation test was conducted at 80 °C showing a power density at a 140 mWcm−2 value, proving the stable nature of synthesized membranes for proton exchange membrane fuel cell application. [ABSTRACT FROM AUTHOR]

A series of hybrid proton exchange membranes were synthesized via in situ polymerization of poly (2-acrylamido-2-methyl-1-propanesulfonic acid) PMPS with sulfonated poly (1,4-phenylene ether-ether-sulfone) (SPEES). The insertion of poly (2-acrylamido-2-methyl-1-propanesulfonic acid) PMPS, between the rigid skeleton of SPEES plays a reinforcing role to enhance the ionic conductivity. The synthesized polymer was chemically characterized by fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance 1H NMR spectroscopy to demonstrate the successful grafting of PMPS with the pendent polymer chain of SPEES. A variety of physicochemical properties were also investigated such as ion exchange capacity (IEC), proton conductivity, water uptake and swelling ratio to characterize the suitability of the formed polymer for various electrochemical applications. SP-PMPS-03, having the highest concentration of all PMPS, shows excellent proton conductivity of 0.089 S cm−1 at 80 °C which is much higher than SPEES which is ~0.049 S cm−1. Optimum water uptake and swelling ratio with high conductivity is mainly attributed to a less ordered arrangement polymer chain with high density of the functional group to facilitate ionic transport. The residual weight was 93.35, 92.44 and 89.56%, for SP-PMPS-01, 02 and 03, respectively, in tests with Fenton's reagent after 24 h. In support of all above properties a good chemical and thermal stability was also achieved by SP-PMPS-03, owing to the durability for electrochemical application. [ABSTRACT FROM AUTHOR]