Enhanced Proton Transfer Research Articles

Enhanced proton transfer in proton exchange membrane fuel cells via novel nanocomposite membrane incorporating (3-Mercaptopropyl)trimethoxysilane-graphene oxide and basic amino ligands: A synergistic acid-base approach

A nanocomposite polymer electrolyte membrane (MGC) was synthesized by blending MPTS (HS(CH2)3Si(OCH3)3) and graphene oxide (GO) nanosheets at varying weight ratios (91.5 to 9.5, respectively) for proton exchange membrane fuel cell (PEMFC) applications. By covalently modifying the GO support with MPTS through a silane modification process, the acidic MGC matrix is formed. The blending process, with ultrasonication and vigorous stirring, initiates two significant reactions in reactive MPTS: first, the conversion of methoxy groups (Si–OCH3) to silanols (Si-OH); second, the potential condensation of silanol groups to form siloxane bonds (Si–O–Si), followed by oxidation of sulfhydryl groups to sulfonic acid (-SO3H) groups by hydrogen peroxide. The resulting -SO3H groups connected to the siloxane network (Si-O-Si) adjacent to the GO. Two basic amino ligands – dopamine, and aminopropyl trimethoxysilane (APTES) were incorporated into the MGC matrix to establish acid-base pairs, promoting swift proton transport. These additions, at weight ratios of (0.5, 1, 2, and 7) wt%, synergistically contributed to the MGC matrix, forming effective proton channels. Various analytical techniques, including field emission-scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), Raman spectroscopy, X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS), were employed to assess the impact of functionalized basic amino groups on the MGC matrix. Notably, the MGC membrane containing 2 wt% of PDA as basic amino ligands exhibited optimal performance, showcasing an in-plane proton conductivity of 115.10 mS cm-1 under fully hydrated conditions at 90 °C, and the maximum power density (MPD) of 170.74 mW cm-2 with a current density of 1051.46 mA cm-2 at 60 °C and 100 % relative humidity (RH). In contrast, the MGC membrane, devoid of amino ligands, exhibited a comparatively low in-plane conductivity of 44.32 mS cm⁻¹ under identical conditions at 90 °C. Additionally, it recorded the MPD of 48.5 mW cm⁻², corresponding to a current density of 313.25 mA cm⁻² at 60 °C and 100 % RH. This study introduces an innovative approach for developing high-performance nanocomposite membranes for PEMs and related applications.

Confinement Effects on Proton Transfer in TiO2 Nanopores from Machine Learning Potential Molecular Dynamics Simulations.

Improved understanding of proton transfer in nanopores is critical for a wide range of emerging applications, yet experimentally probing mechanisms and energetics of this process remains a significant challenge. To help reveal details of this process, we developed and applied a machine learning potential derived from first-principles calculations to examine water reactivity and proton transfer in TiO2 slit-pores. We find that confinement of water within pores smaller than 0.5 nm imposes strong and complex effects on water reactivity and proton transfer. Although the proton transfer mechanism is similar to that at a TiO2 interface with bulk water, confinement reduces the activation energy of this process, leading to more frequent proton transfer events. This enhanced proton transfer stems from the contraction of oxygen-oxygen distances dictated by the interplay between confinement and hydrophilic interactions. Our simulations also highlight the importance of the surface topology, where faster proton transport is found in the direction where a unique arrangement of surface oxygens enables the formation of an ordered water chain. In a broader context, our study demonstrates that proton transfer in hydrophilic nanopores can be enhanced by controlling pore size, surface chemistry, and topology.

Confinement effect of FeMOFs glass enhances the proton coupled electron transfer reaction for the organic pollutants polymerization toward sustainable water purification

Polymerization-driven removal of pollutants in advanced oxidation processes (AOPs) offers a sustainable way for the simultaneous achievement of contamination abatement and resource recovery, supporting a low-carbon water purification approach. In this work, metal–organic frameworks (MOFs) glass complexes (g-ZIF-62@8) were used as a platform to enhance proton transfer through the confinement effect of nanopores, modulating proton coupled electron transfer (PCET) reaction to promote organic pollutant polymerization. The results show that the confinement effect of nanopores in ZIF-62 glass can significantly improve the proton and electron transfer behavior, the proton diffusion coefficient is increased by 4.9 times (2.91*10−3 to 1.43*10−2), the energy barrier of the PCET reaction can be reduced by 1.9 eV, and the reaction kinetic rate constant is increased from 0.0198 min−1 to 0.20118 min−1. Photogenerated holes and Fe(IV = O), as the main reactive oxygen species (ROS), undergo PCET reaction with Bisphenol A (BPA) to convert them into phenoxy radicals, which are then polymerized into macromolecular organic compounds. PCET with proton-electron synergy was identified as a key driver of pollutant polymerization. This enables low-carbon purification and organic carbon recovery in wastewater. Our work provides new insights into the application of confinement effects to enhance proton and electron behavior to regulate pollutant polymerization toward sustainable water purification.

Enhanced Proton Transfer in Proton-Exchange Membranes with Interconnected and Zwitterion-Functionalized Covalent Porous Material Structures.

Excellent proton-conductive accelerators are indispensable for efficient proton-exchange membranes (PEMs). Covalent porous materials (CPMs), with adjustable functionalities and well-ordered porosities, show much promise as effective proton-conductive accelerators. In this study, an interconnected and zwitterion-functionalized CPM structure based on carbon nanotubes and a Schiff-base network (CNT@ZSNW-1) is constructed as a highly efficient proton-conducting accelerator by in situ growth of SNW-1 onto carbon nanotubes (CNTs) and subsequent zwitterion functionalization. A composite PEM with enhanced proton conduction is acquired by integrating CNT@ZSNW-1 with Nafion. Zwitterion functionalization offers additional proton-conducting sites and promotes the water retention capacity. Moreover, the interconnected structure of CNT@ZSNW-1 induces a more consecutive arrangement of ionic clusters, which significantly relieves the proton transfer barrier of the composite PEM and increases its proton conductivity to 0.287 S cm-1 under 95 % RH at 90 °C (about 2.2 times that of the recast Nafion, 0.131 S cm-1 ). Furthermore, the composite PEM displays a peak power density of 39.6 mW cm-2 in a direct methanol fuel cell, which is significantly higher than that of the recast Nafion (19.9 mW cm-2 ). This study affords a potential reference for devising and preparing functionalized CPMs with optimized structures to expedite proton transfer in PEMs.

Subpicosecond Molecular Rearrangements Affect Local Electric Fields and Auto-Dissociation in Water.

Molecular simulations of auto-dissociation of water molecules in an 81,000 atom bulk water system show that the electric field variations caused by local bond length and angle variations enhance proton transfer within ∼600 fs prior to auto-dissociation. In this paper, auto-dissociation relates to the initial separation of a proton from a water molecule to another, forming the H33O+ and OH- ions. Only transfers for which a proton's initial nearest covalently bonded oxygen remained the same for at least 1 ps prior to the transfer and for which that proton's new nearest acceptor oxygen remained the same for at least 1 ps after the transfer were evaluated. Electric fields from solvent atoms within 6 Å of a transferring proton (H*) are dominant, with little contribution from farther molecules. However, exclusion of the accepting oxygen in such electric field calculations shows that the field on H* from the other solvent atoms weakens as the time to transfer becomes less than 600 fs, indicating the primary importance of the accepting oxygen on enabling auto-dissociation. All resultant OH- and H3O+ ion pairs recombined at times greater than 1 ps after auto-dissociation. A concentration of 8.01 × 1017 cm-3 for these ion pairs was observed. The simulations indicate that transient auto-dissociation in water is more common than that inferred from dc-conductivity experiments (10-5 vs 10-7) and is consistent with the results of calculations that include nuclear quantum effects. The conductivity experiments require the rearrangement of farther water molecules to form hydrogen-bonded "water wires" that afford long-range and measurable proton transport away from the reaction site. Nonetheless, the relatively large number of picosecond-lived auto-dissociation products might be engineered within 2D layers and oriented external fields to offer new energy-related systems.

Polarization Engineering of Covalent Triazine Frameworks for Highly Efficient Photosynthesis of Hydrogen Peroxide from Molecular Oxygen and Water.

Two-electron oxygen photoreduction to hydrogen peroxide (H2 O2 ) is seriously inhibited by its sluggish charge kinetics. Herein, a polarization engineering strategy is demonstrated by grafting (thio)urea functional groups onto covalent triazine frameworks (CTFs), giving rise to significantly promoted charge separation/transport and obviously enhanced proton transfer. The thiourea-functionalized CTF (Bpt-CTF) presents a substantial improvement in the photocatalytic H2 O2 production rate to 3268.1µmol h-1 g-1 with no sacrificial agents or cocatalysts that is over an order of magnitude higher than unfunctionalized CTF (Dc-CTF), and a remarkable quantum efficiency of 8.6% at 400nm. Mechanistic studies reveal the photocatalytic performance is attributed to the prominently enhanced two-electron oxygen reduction reaction by forming endoperoxide at the triazine unit and highly concentrated holes at the thiourea site. The generated O2 from water oxidation is subsequently consumed by the oxygen reduction reaction (ORR), thereby boosting overall reaction kinetics. The findings suggest a powerful functional-groups-mediated polarization engineering method for the development of highly efficient metal-free polymer-based photocatalysts.

Confirmation of supramolecular structure and its impact on nonlinear optical properties of Bis(4-methylbenzylammonium) tetrabromido zincate: A new semiorganic crystal

Supramolecular structure exhibits good nonlinear optical (NLO) properties due to the enhanced proton transfer process. Semiorganic Bis(4-methylbenzylammonium) tetrabromido zincate (4MLTBZ) crystal was developed by functionalizing 4-methylbenzylamine (4MLBA) with hydrobromic acid and zinc bromide. Amine group of 4MLBA gets protonated by H+ cation of hydrobromic acid. Zinc bromide was linked with 4MLBA through CH ⋯Br and NH ⋯Br interactions which forms supramolecular structure and crystallized noncentrosymmetric space group Pna21. Raman and FTIR spectral analysis provides the evidence for the protonation of amine (NH3+) group. Raman spectrum reveals the coordination of ZnBr4 in 4MLTBZ crystal structure through the observed ZnBr vibrations between 50 and 400 cm−1. The impact over the shift in vibrational frequencies of NH and CH functional groups due to CH ⋯Br and NH ⋯Br interactions were discussed. The ‘CarbonHydrogen’ frame work of 4MLTBZ crystal was established by 1H NMR and 13C NMR spectroscopy. The UV–Vis–NIR spectrum of 4MLTBZ showed very good transparency in the region from 260 nm to 1100 nm. The enhanced SHG efficiency and third order nonlinear optical susceptibility (χ3) are interpreted through hydrogen bonds.

Enhanced protonic conductivity and IFET behavior in individual proton-doped electrospun chitosan fibers

Enhanced proton transfer of an electrospun, single chitosan fiber doped by TFA in the presence of hydrogen in 75% relative humidity.

A self-recirculation electrolyte system for unbuffered microbial fuel cells with an aerated cathode

A self-recirculation electrolyte system driven by air bubble buoyancy force is proposed for unbuffered microbial fuel cells (MFC) in this study. It was demonstrated that the electrolyte recirculation rate increased with the aeration rate in a certain range. Compared with buffer condition, buffer-less condition resulted in a 10%∼20% lower voltage (14.2% lower maximum power density) but a 9.1% higher Coulombic efficiency (CE) at an aeration rate of 92.0ml/min. Under buffer-less condition, increasing the aeration rate resulted in a higher voltage output, a higher COD removal, and a higher CE due to the enhanced proton transfer and increased oxygen for cathode reaction. However, an extra high aeration rate induced a rapid deterioration of anode performance due to the excessive oxygen transfer into anode. This study demonstrates that the self-recirculation electrolyte system could be helpful for future unbuffered MFC designs.

Step-feed strategy enhances performance of unbuffered air-cathode microbial fuel cells

Step-feed was introduced to enhance proton transfer in unbuffered MFCs and improved power generation and Coulombic efficiency.

Effect of proton transfer on the performance of unbuffered tubular microbial fuel cells in continuous flow mode

Microbial fuel cells (MFCs) require a better understanding of proton transfer especially under buffer-less condition for practical application. In this study, two continuous-flow tubular MFCs using separators with either low (MFC-LPP) or high proton permeability (MFC-HPP) were operated under buffer-less condition. The results showed that MFC-HPP had a better cathode performance and 125% higher maximum power density than MFC-LPP. The higher performance of MFC-HPP was mainly attributed to the enhanced proton transfer and increased catholyte conductivity, suggesting that the proton transfer from the anode to the cathode was crucial to the performance of unbuffered MFCs. It was also found that promoting the proton transfer by increasing the electrolyte flow rate led to a further performance improvement of MFC-HPP. Based on energy efficiency analysis, additional energy gain can be obtained from the unbuffered MFCs when it was operated below a critical flow rate.

Anolyte recirculation effects in buffered and unbuffered single-chamber air-cathode microbial fuel cells

Two identical microbial fuel cells (MFCs) with a floating air-cathode were operated under either buffered (MFC-B) or bufferless (MFC-BL) conditions to investigate anolyte recirculation effects on enhancing proton transfer. With an external resistance of 50Ω and recirculation rate of 1.0ml/min, MFC-BL had a 27% lower voltage (9.7% lower maximal power density) but a 64% higher Coulombic efficiency (CE) than MFC-B. MFC-B had a decreased voltage output, batch time, and CE with increasing recirculation rate resulting from more oxygen transfer into the anode. However, increasing the recirculation rate within a low range significantly enhanced proton transfer in MFC-BL, resulting in a higher voltage output, a longer batch time, and a higher CE. A further increase in recirculation rate decreased the batch time and CE of MFC-BL due to excess oxygen transfer into anode outweighing the proton-transfer benefits. The unbuffered MFC had an optimal recirculation rate of 0.35ml/min.

Evaluation of the Electrospun Inorganic/Organic Composite Membrane for High Temperature PEMFC

Abstrast High temperature fuel cell has been highlighted for its use in the wide range of the applications because of its simplified system due to easier integration and high energy efficiency.[1-2] There are several fascinating reasons for operating PEMFC at high temperature and low related humidity such as electrochemical kinetics, CO poisoning of Pt/C catalyst and water management. Also, the lifetime targets (5000 h stated objective by DOE) must be achieved while the costs of the fuel cell systems must be reduced concurrently.[1] In order to ameliorate the durability and lifetime of PEMFCs, a better analyzing of failure tools and corresponding mitigation methods are urgently required.[2] In the development of membranes that can effectively operate under higher temperature and lower humidity conditions, researchers have suggested organic-inorganic composite membranes with inorganic particulate additives.[3] Some of the composite membranes with particulate additives have shown improved fuel cell performance at high temperature and low humidity because of improved hydroscopic and thermal stability. Nevertheless, in practice, composite film casting by solvent evaporation or extrusion is often challenging due to particle agglutination. Recently, ceramic nanofibers have been prepared via electrospinning.[4] The uniformly dispersed 3-dimensional foam-like inorganic nanofibrous web completely resolved the agglomeration issue of particulate additives. The aspect ratio of the fibers was extremely high thereby providing additional mechanical strength to the composite membrane that could not be achieved by particulate additives.In this study, we prepared inorganic nanofibrous web supported polymer electrolyte membrane to increase operating temperature of the pristine polymer electrolyte membrane. Accelerated life-time tests (ALT) by changing the voltage sweep were developed to have better understanding of the degradation mechanisms in the fuel cell system. Further, factors of degradation were studied by conducting the electrochemical methods and characterizations.Gravimetric swelling by water of the Aquivion-impregnated inorganic nanofibrous webs as a membrane was higher than Aquivion cast film (32.8% vs. 17.5%) but more importantly, no length change in x- and y-axis was observed in wet state due to the presence of rigid inorganic nanofibrous webs uniformly distributed in the membrane. Therefore, no areal expansion of membrane is expected in the actual fuel cell test that would be beneficial to mechanically stable operation. A single cell with Aquivion/phosphate modified inorganic nanofiber composite membrane showed the best performance at partially humidified condition of 120 °C / 40% RH. It was expected that the higher water retention of the Aquivion/ phosphate modified inorganic nanofiber composite membrane played a beneficial role that the phosphate functionality enhanced proton conductivity by enhancing proton transfer through the Grotthus mechanism at higher temperature and the lower humidity conditions.

Improved interfacial oxygen reduction by ethylenediamine tetraacetic acid in the cathode of microbial fuel cell

In this study, ethylenediamine tetraacetic acid (EDTA) was investigated as a new kind of non-polymeric catalyst binder to improve interfacial oxygen reduction reaction (ORR) for the cathode of microbial fuel cell (MFC). The electrochemical analysis and MFC tests show negative correlation between ORR activity and molar concentration of EDTA applied during electrode preparation. In particular, the 0.02mol/L-EDTA yields higher ORR activity than other binder materials like Nafion, water, 0.1mol/L-EDTA and 0.2mol/L-EDTA, as indicated by the strongest response of ORR current and the smallest charge-transfer resistance. Accordingly, the MFC with cathode of 0.02mol/L-EDTA produced a maximum power density of 722mW/m2, accounting for a value approximately 42% higher than that of commercial Nafion binder (5wt%, 507mW/m2). The improved ORR activity should be attributed to the enhanced proton transfer from phosphate ions to EDTA-involved three-phase boundary as a result of dipole ion bonds on nitrogen atoms having unshared pair of electrons in EDTA molecule.

Fluorescence indicative pH drop in sonication

Sonication induces complex chemical and physical phenomena in solution, which attracted great attentions to discover the mechanisms behind these phenomena. One of these phenomena is the pH drop in sonication, which was usually attributed to the formation of nitrate and nitrite acid in sonication. However, the pH drop detected by electrodes was questioned since the sonication could enhance proton transfer on the surface of pH electrode, resulting in a false pH drop. Therefore, it is necessary to initiate a tour study on this issue. In this paper, we firstly investigate two new factors, namely CO2 dissolution and temperature, which have the possibility to induce the pH drop in sonication. The results demonstrate that both factors play a minor role on the pH drop. Then we employ pH sensitive dyes to replace the questioned pH electrode to detect the change of proton concentration in sonication. The results indicate that the pH drop is accompanied with the protonation of fluorescein, indicating production of hydrogen ions in sonication. The quantitative analysis of proton production suggests that the pH drop in sonication is mainly caused by the formation of hydrogen ions, which clarify the reason for the pH drop in sonication.

Polydopamine-modified graphene oxide nanocomposite membrane for proton exchange membrane fuel cell under anhydrous conditions

A new approach to the facile preparation of anhydrous proton exchange membrane (PEM) enabled by artificial acid–base pairs is presented herein. Inspired by the bioadhesion of mussel, polydopamine-modified graphene oxide (DGO) sheets bearing –NH2 and –NH– groups are fabricated and then incorporated into sulfonated poly(ether ether ketone) (SPEEK) matrix to prepare the nanocomposite membrane. The DGO sheets are interconnected and homogeneously dispersed in SPEEK matrix, which provides unique rearrangement of the nanophase-separated structure and chain packing of nanocomposite membrane through interfacial electrostatic attractions. These attractions meanwhile induce the generation of acid–base pairs along the SPEEK–DGO interface, which then serve as long-range and low-energy-barrier pathways for proton hopping, imparting an enhanced proton transfer via the Grotthuss mechanism. In particular, under both hydrated and anhydrous conditions, the nanocomposite membrane exhibits much higher proton conductivity than the polymer control membrane. The enhanced proton conductivity results in the nanocomposite membrane having elevated cell performances under 120 °C and hydrous conditions, yielding a 47% increase in maximum current density and a 38% increase in maximum power density. Together with the stable conduction property, these results guarantee the nanocomposite membrane's promising prospects in high-performance fuel cell under anhydrous and elevated temperature conditions.

Enhanced proton conduction of chitosan membrane enabled by halloysite nanotubes bearing sulfonate polyelectrolyte brushes

Currently, enhancing the proton conductivity is one challenge for chitosan (CS, an industrial waste around the world) membrane to work as proton exchange membrane for direct methanol fuel cell. In this study, halloysite nanotubes bearing sulfonate polyelectrolyte brushes (SHNTs) are synthesized via distillation–precipitation polymerization and then incorporated into CS matrix to fabricate nanohybrid membranes. The membranes are characterized using field emission scanning electron microscope, fourier transform infrared, thermogravimetric analysis, differential scanning calorimetry, and mechanical tester. It is found that SHNTs generate strong electrostatic attractions to CS chains, which inhibit the chain mobility and thus enhance the thermal and mechanical stabilities of nanohybrid membranes. The results of water uptake, area swelling, proton conductivity, and activation energy reveal that the high aspect nanotube and long polyelectrolyte brush allow SHNTs to construct continuous and wide pathways, along which sulfonic acid–amide acid–base pairs are formed and work as low-barrier proton-hoping sites, imparting an enhanced proton transfer via Grotthuss mechanism. In such a way, the proton conductivity of CS membrane is obviously enhanced, and 15% SHNTs can afford a 60% enhancement in conductivity to the nanohybrid membrane, particularly. Moreover, the methanol permeability and selectivity of the as-prepared membranes are investigated in detail.

Synthesis and application of ionic liquid matrices (ILMs) for effective pathogenic bacteria analysis in matrix assisted laser desorption/ionization (MALDI-MS)

Application of two new series of ionic liquid matrices (ILMs) based on the two most predominantly used conventional organic matrices (Sinapinic acid and 2,5-DHB) in conjugation with various bases (aniline (ANI), dimethyl aniline (DMANI), diethylamine (DEA), dicyclohexylamine (DCHA), pyridine (Pyr), 2-picoline(2-P), 3-picoline(3-P)) for bacterial analysis in matrix assisted laser desorption/ionisation mass spectrometry (MALDI-MS) are reported. The results reveal that ionic liquid matrices could significantly enhance the protein signals, reduce spot-to-spot variation and increase spot homogeneity. More importantly, these novel matrices would not produce any interference during MALDI-MS analysis. Among these ILMs, 2,5-DHB/ANI, 2,5-DHB/DMANI and 2,5-DHB/Pyr can be successfully applied to intact bacterial studies compared with other ILMs. Base molecules when added to conventional matrix can promote proton transfer between the bacterial lysate and the matrices. Due to the enhanced proton transfer efficiency by the ionic liquid matrices, almost all the biomolecules of the intact bacterial cells can be ionized and detected in the MALDI-MS. All synthesized ILMs were characterized using ESI (+)/MS and UV-spectroscopy.

Assimilation of highly porous sulfonated carbon nanospheres into Nafion® matrix as proton and water reservoirs

A unique form of carbon nanospheres possessing an immense number of micropores and pendant surface sulfonic acid groups was synthesized and used as an effective filler to enhance proton transfer in Nafion® membrane at elevated temperatures. The synthesis of the filler involved the formation of polypyrrole nanoparticles and pyrolysis of them to generate carbon nanospheres (CN). Alkaline etching was then carried out to create the porous structure, and the resulting porous carbon nanospheres were then sulfonated to attain the sulfonated porous carbon nanospheres (sPCN, 1300 m2/g, 6.9 mmol-SO3H/g). Dispersion of a substantially small amount of sPCN in a Nafion matrix brought about a cross-adsorption between the hydrophilic side-chain of Nafion molecules and sPCN. This causes the formation of a cross-linking network with sPCN junctions. The scope of this network, however, decreased with the increase in the sPCN loading from 1 to 2 wt% due to a reduction in extent of the cross-adsorption. The sPCN loading of 1 wt% reached the highest crosslinking degree that displayed the maximum enhancement on proton transport. It can be attributed to the role of the sPCN crosslinking junctions in keeping moisture and supplying protons. The characterizations of glass transition behaviour, hydrophilic microenvironments, and proton conductivity under low humidity levels reflected the impact of crosslinking extent. In the single H2-PEMFC test at 70 °C using dry H2/O2, 1 wt%-sPCN Nafion composite membrane manifested a power density of 571 mW/cm2 as compared to the pristine Nafion membrane that showed uppermost value of 388 mW/cm2.

Enhancement of Proton Conduction at Low Humidity by Incorporating Imidazole Microcapsules into Polymer Electrolyte Membranes

AbstractDesign and fabrication of hierarchically structured membranes with high proton conductivity is crucial to many energy‐relevant applications including proton exchange membrane fuel cell (PEMFC). Here, a series of imidazole microcapsules (IMCs) with tunable imidazole group loading, shell thickness, and lumen size are synthesized and incorporated into a sulfonated poly(ether ether ketone) (SPEEK) matrix to prepare composite membranes. The IMCs play two roles: i) Improving water retention properties of the membrane. The IMCs, similar to the vacuoles in plant cells, can render membrane a stable water environment. The lumen of the IMCs acts as a water reservoir and the shell of IMCs can manipulate water release. ii) They form anhydrous proton transfer pathways and low energy barrier pathways for proton hopping, imparting an enhanced proton transfer via either a vehicle mechanism or Grotthuss mechanism. In particular, at the relative humidity (RH) as low as 20%, the composite membrane exhibits an ultralow proton conductivity decline and the proton conductivity is one to two orders of magnitude higher than that of SPEEK control membrane. The enhanced proton conductivity affords the composite membrane an elevated peak power density from 69.5 to 104.5 mW cm−2 in a single cell. Moreover, the application potential of the composite membrane for CO2 capture is explored.