28 research outputs found
An Investigation of a (vinylbenzyl) trimethylammonium and N-vinylimidazole-substituted poly (vinylidene fluoride-co-hexafluoropropylene) copolymer as an anion-exchange membrane in a lignin-oxidising electrolyser
Electrolysis is seen as a promising route for the production of hydrogen from water, as part of a move to a wider “hydrogen economy”. The electro-oxidation of renewable feedstocks offers an alternative anode couple to the (high-overpotential) electrochemical oxygen evolution reaction for developing low-voltage electrolysers. Meanwhile, the exploration of new membrane materials is also important in order to try and reduce the capital costs of electrolysers. In this work, we synthesise and characterise a previously unreported anion-exchange membrane consisting of a fluorinated polymer backbone grafted with imidazole and trimethylammonium units as the ion-conducting moieties. We then investigate the use of this membrane in a lignin-oxidising electrolyser. The new membrane performs comparably to a commercially-available anion-exchange membrane (Fumapem) for this purpose over short timescales (delivering current densities of 4.4 mA cm−2 for lignin oxidation at a cell potential of 1.2 V at 70 °C during linear sweep voltammetry), but membrane durability was found to be a significant issue over extended testing durations. This work therefore suggests that membranes of the sort described herein might be usefully employed for lignin electrolysis applications if their robustness can be improved
Dramatic Improvement in Water Retention and Proton Conductivity in Electrically Aligned Functionalized CNT/SPEEK Nanohybrid PEM
Nanohybrid membranes of electrically
aligned functionalized carbon
nanotube <i>f</i> CNT with sulfonated poly ether ether ketone
(SPEEK) have been successfully prepared by solution casting. Functionalization
of CNTs was done through a carboxylation and sulfonation
route. Further, a constant electric field (500 V·cm<sup>–2</sup>) has been applied to align CNTs in the same direction during the
membrane drying process. All the membranes are characterized chemically,
thermally, and mechanically by the means of FTIR, DSC, DMA, UTM, SEM,
TEM, and AFM techniques. Intermolecular interactions between the components
in hybrid membranes are established by FTIR. Physicochemical measurements
were done to analyze membrane stability. Membranes are evaluated for
proton conductivity (30–90 °C) and methanol crossover
resistance to reveal their potential for direct methanol fuel cell
application. Incorporation of <i>f</i> CNT reasonably increases
the ion-exchange capacity, water retention, and proton conductivity
while it reduces the methanol permeability. The maximum proton conductivity
has been found in the S-sCNT-5 nanohybrid PEM with higher methanol
crossover resistance. The prepared membranes can be also used for
electrode material for fuel cells and batteries
Dramatic Improvement in Ionic Conductivity and Water Desalination Efficiency of SGO Composite Membranes
<div><p>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<sup>−2</sup> S/cm), which is almost double to the SPES with higher stability. SGO-5 membrane shows 4.73 mole.m<sup>−2</sup>h<sup>−1</sup> ionic flux, 0.98 kWhkg<sup>−1</sup> power 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.
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An Investigation of a (Vinylbenzyl) Trimethylammonium and N-Vinylimidazole-Substituted Poly (Vinylidene Fluoride-Co-Hexafluoropropylene) Copolymer as an Anion-Exchange Membrane in a Lignin-Oxidising Electrolyser
Electrolysis is seen as a promising route for the production of hydrogen from water, as part of a move to a wider “hydrogen economy.” The electro-oxidation of renewable feedstocks offers an alternative anode couple to the (high-overpotential) electrochemical oxygen evolution reaction for developing low-voltage electrolysers. Meanwhile, the exploration of new membrane materials is also important in order to try and reduce the capital costs of electrolysers. In this work, we synthesise and characterise a previously unreported anion-exchange membrane consisting of a fluorinated polymer backbone grafted with imidazole and trimethylammonium units as the ion-conducting moieties. We then investigate the use of this membrane in a lignin-oxidising electrolyser. The new membrane performs comparably to a commercially-available anion-exchange membrane (Fumapem) for this purpose over short timescales (delivering current densities of 4.4 mA cm−2 for lignin oxidation at a cell potential of 1.2 V at 70 °C during linear sweep voltammetry), but membrane durability was found to be a significant issue over extended testing durations. This work therefore suggests that membranes of the sort described herein might be usefully employed for lignin electrolysis applications if their robustness can be improved
Enhanced Electrochemical Performance of Stable SPES/SPANI Composite Polymer Electrolyte Membranes by Enriched Ionic Nanochannels
Herein, we present the results of
sulfonated polyaniline (SPANI)
and sulfonated poly(ether sulfone) (SPES) composite polymer electrolyte
membranes. The membranes are established for high-temperature proton
conductivity and methanol permeability to render their applicability.
Composite membranes have been prepared by modifying the SPES matrix
with different concentrations of SPANI (e.g., 1, 2, 5, 10, and 20
wt %). Structural and thermomechanical characterizations have been
performed using the transmission electron microscopy, differential
scanning calorimetry, thermogravimetric analysis, and dynamic mechanical
analyzer techniques. Physicochemical and electrochemical properties
have been evaluated by water uptake, ion-exchange capacity, dimensional
stability, and proton conductivity. Methanol permeability experiment
was carried out to analyze the compatibility of prepared membranes
toward direct methanol fuel cell application and found the lowest
methanol permeability for PAS-5. Also, the membranes reveal excellent
thermal, mechanical, and physicochemical properties for their application
toward high-temperature electromembrane processes
Enhanced Electrochemical Performance of Stable SPES/SPANI Composite Polymer Electrolyte Membranes by Enriched Ionic Nanochannels
Herein, we present the results of
sulfonated polyaniline (SPANI)
and sulfonated poly(ether sulfone) (SPES) composite polymer electrolyte
membranes. The membranes are established for high-temperature proton
conductivity and methanol permeability to render their applicability.
Composite membranes have been prepared by modifying the SPES matrix
with different concentrations of SPANI (e.g., 1, 2, 5, 10, and 20
wt %). Structural and thermomechanical characterizations have been
performed using the transmission electron microscopy, differential
scanning calorimetry, thermogravimetric analysis, and dynamic mechanical
analyzer techniques. Physicochemical and electrochemical properties
have been evaluated by water uptake, ion-exchange capacity, dimensional
stability, and proton conductivity. Methanol permeability experiment
was carried out to analyze the compatibility of prepared membranes
toward direct methanol fuel cell application and found the lowest
methanol permeability for PAS-5. Also, the membranes reveal excellent
thermal, mechanical, and physicochemical properties for their application
toward high-temperature electromembrane processes