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Solid anion exchange membrane (AEM) electrolytes are an essential commodity considering their importance as separators in alkaline polymer electrolyte fuel cells (APEFC). Mechanical and thermal stability are distinguished by polymer matrix characteristics, whereas anion exchange capacity, transport number, and conductivities are governed by the anionic group. The physico-chemical stability is regulated mostly by the polymer matrix and, to a lesser extent, the cationic head framework. The quaternary ammonium (QA), phosphonium, guanidinium, benzimidazolium, pyrrolidinium, and spirocyclic cation-based AEMs are widely studied in the literature. In addition, ion solvating blends, hybrids, and interpenetrating networks still hold prominence in terms of membrane stability. To realize and enhance the performance of an alkaline polymer electrolyte fuel cell (APEFC), it is also necessary to understand the transport processes for the hydroxyl (OH−) ion in anion exchange membranes. In the present review, the radiation grafting of the monomer and chemical modification to introduce cationic charges/moiety are emphasized. In follow-up, the recent advances in the synthesis of anion exchange membranes from poly(phenylene oxide) via chloromethylation and quaternization, and from aliphatic polymers such as poly(vinyl alcohol) and chitosan via direct quaternization are highlighted. Overall, this review concisely provides an in-depth analysis of recent advances in anion exchange membrane (AEM) and its viability in APEFC. [ABSTRACT FROM AUTHOR]

Pd–Y 2 O 3 on carbon (Pd–Y 2 O 3 /C) in different mass ratios of Pd to Y 2 O 3 (1:1, 2:1, 3:1) were prepared and subjected as cathode electrocatalyst for polymer electrolyte fuel cells (PEFC). X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to determine the structure, crystalline size and dispersion of Pd–Y 2 O 3 /C respectively. The electrochemical characterizations of the electrocatalysts were evaluated from Cyclic Voltammetry (CV) and Linear Sweep Voltammetry (LSV). These electrocatalysts were evaluated for their catalytic activity towards oxygen reduction reaction (ORR) in fuel cell. Pd 2 –Y 2 O 3 /C catalyst shows higher power density of 325 mW cm−2 than Pd 1 –Y 2 O 3 /C, Pd 3 –Y 2 O 3 /C and Pd/C. • Various atomic ratios of Pd–Y 2 O 3 /C prepared and evaluated as ORR catalyst for PEFC. • Pd 2 –Y 2 O 3 /C as a cathode catalyst shows high peak power density of 325 mW cm−2. • Pd 2 –Y 2 O 3 /C exhibits higher ORR activity due to SMSI effect. [ABSTRACT FROM AUTHOR]

In this article, pre-assembly hot-press pressure and thermal expansion effects in gas-diffusion layers (GDLs) are addressed to explore the practicalities of the constitutive model reported in the companion article. A facile technique is proposed to include deformation history dependent residual strain effects. The model is implemented in the numerical environment and compared with widely followed conventional models such as isotropic and orthotropic material models. With the normal and accelerated thermal expansion effects no significant variation in stresses or strains is reported with the compressible GDL model in contrast to the conventional incompressible form of the GDL model. The present work identifies the critical differences with advanced and extended variants of the model along with conventional GDL material models in terms of planar stress/strain distribution and the membrane response. Finally, the model is simulated for micro-cyclic stress loads of varying amplitudes that imitate the real working conditions of fuel cell. The inelastic energy dissipation in GDLs is predicted using the proposed model, which is utilized further to distinguish the safe (elastic) and unsafe (inelastic shakedown) operating limits. The inelastic collapse of GDLs is shown to be a active function of high amplitude micro-cyclic load with high initial clamping load. [Display omitted] • Thermomechanical stability of fuel cell GDL is reported. • Numerical implementation of advanced compressible GDL model is presented. • Influence of pre-fabrication hot-press pressure effect is modeled. • A GDL failure criteria is stated in terms of inelastic dissipation energy and microstress cycles. [ABSTRACT FROM AUTHOR]

Nitrogen and carbon doped titanium oxide as an alternative and ultra-stable support to platinum catalysts is prepared and its efficiency is determined by polymer electrolyte fuel cell. Nitrogen and carbon doped titanium oxide is prepared by varying the melamine ratio followed by calcination at 900 °C. Platinum nanoparticles are deposited onto doped and undoped titanium oxide by colloidal method. The doping effect, surface morphology, chemical oxidation state and metal/metal oxide interfacial contact are studied by X-ray diffraction, Raman spectroscopy, high resolution transmission electron microscopy and X-ray photo electron spectroscopy. The nitrogen and carbon doping changes both electronic and structural properties of titanium oxide resulting in enhanced oxygen reduction reaction activity. The platinum deposited on optimum level of nitrogen and carbon doped titanium oxide exhibits improved cell performance in relation to platinum on titanium oxide electrocatalysts. The effect of metal loading on cathode electrocatalyst is investigated by steady-state cell polarization. Accelerated durability test over 50,000 cycles for these electrocatalysts suggested the improved interaction between platinum and nitrogen and carbon doped titanium oxide, retaining the electrochemical surface area and oxygen reduction performance as comparable to platinum on carbon support. [ABSTRACT FROM AUTHOR]

Nanocomposite membranes of sulfonated polyether ether ketone (sPEEK) are prepared with polyaminobenzene sulfonic acid grafted single-walled carbon nanotubes copolymer (PABS-SWCNT) and its zwitterion interactions are studied. The nanocomposite membranes are prepared through solution cast technique using PABS-SWCNT as additive in different weight % (0.1, 0.15, and 0.2) ratio. The additive and nanocomposite membranes are characterized for its surface morphology, composition, thermal and physico-chemical properties. The nanocomposite membrane comprising optimized content of PABS-SWCNT (0.15 wt %) shows improved proton conductivity and reduced methanol crossover resulting in enhanced DMFC peak power density of 150 mW cm−2 in comparison to 110 mW cm−2 for sPEEK and 80 mW cm−2 for Nafion® 117 respectively. The improved durability till 100 h for sPEEK/PABS-SWCNT (0.15 wt %) compared to sPEEK and Nafion-117 confirms its viability in DMFC application. Zwitterion interaction between sulfonic acid and amine groups for sPEEK/PABS-SWCNT (0.15 wt %) nanocomposite membrane facilitate ion transport along with significant restriction in methanol permeability for enhanced direct methanol fuel cell power output. Image 1 • Nanocomposite membrane using PABS-SWCNT copolymer with sPEEK is synthesized. • sPEEK/PABS-SWCNT (0.15 wt%) membrane shows enhanced physico-chemical properties. • Nanocomposite membranes show 50% reduction in methanol crossover compared to sPEEK. • sPEEK/PABS-SWCNT shows enhanced DMFC performance with better durability. • DMFC performance is 85% higher for sPEEK/PABS-SWCNT in comparison to Nafion®. [ABSTRACT FROM AUTHOR]

Abstract Optimum amount of carbon semi-coated on titania nanorods-Pt (Pt/CCT) electrocatalyst increases the cell performance and long term durability in low-temperature polymer electrolyte fuel cells (LT-PEFC). Semi-coated carbon on titania nanorods support (CCT) is synthesised hydrothermally followed by Pt deposited using polyol method. A thin metal loading of 150 μg cm−2 with an active area of 50 cm2 exhibits a high current of 49 ± 0.5 A at 0.6 V for 100 h without back pressure in H 2 :O 2 configuration. In the present study, 5 and 15 cell LT-PEFC stacks and their engineering aspects towards development of indigenous cell fixture and assembly are explored in detail. The 5 cell stack durability at 5 A for 125 h shows a minimal voltage loss of 4 μV h−1. In addition, 15 cell air cooled prototype indigenous fuel cell fixture is fabricated and demonstrated with electrical power of 310 W at 9 V. In a single cell, Pt/CCT retains 85% of initial current at 0.6 V during start-stop cycles (100 h) in H 2 :air configuration as compared to Pt/C. Highlights • Carbon is semi-coated on titania nanorods to act as catalyst support. • Pt nanoparticles deposited on CCT by polyol method. • Pt/CCT electrocatalyst is subjected at the cathode in LT-PEFC. • LT-PEFC stack designed and fabricated using indigenous catalyst. • LT-PEFC 15 cell stack durability is addressed. [ABSTRACT FROM AUTHOR]