Enhanced Proton Conductivity Research Articles

Unveiling exceptional conduction mechanism and high proton conductivity in amorphous electrolyte for advanced ceramic fuel cells

The requirement of high ion conductive material working at low temperatures is highly demanding in fuel cells. This study explains a groundbreaking advancement in ceramic fuel cells by exploring the potential of amorphous Sm0.3Al0.7-oxide and the proton conduction mechanism of amorphous oxides. Opposite to conventional crystalline electrolytes, amorphous electrolytes showed superior ion conduction. To study the detailed mechanism of ion conduction, amorphous Sm0.3Al0.7-oxide was selected which exhibited an exceptional proton conductivity of 0.17 S/cm and a power density of 1100 mW/cm2 at 550 °C, significantly surpassing traditional electrolyte materials. Using advance characterization techniques, a new approach has been proposed to provide the reasons for the high conductivity of amorphous materials, which entails a complete mechanism that describes how disordered structure and disoriented grain boundaries facilitate efficient proton conduction by reducing energy barriers and enhancing ionic mobility. Also, it has been described how the high enthalpy and the high energy state of amorphous materials are suitable for enhancing proton conduction. This study aims to clarify why amorphous materials are promising candidates for future fuel cell applications, facilitating significant advancements in SOFC and PCFC technologies and paving the way for more efficient and sustainable energy solutions.

A Novel Strategy to Construct Metal–Organic Frameworks‐Based Memristor with Enhanced Proton Conduction

The limited conductivity of metal‐organic frameworks (MOFs) poses a significant challenge to their application in the domain of memristors. The proton conduction capabilities of MOFs can be improved through the incorporation of guest molecules. Herein, hydrogen protons are introduced into MIL‐53 (Al) via acid leaching, which not only enhances the proton conductivity of MIL‐53 (Al) but also contributes to its superior resistance switching behavior. The results indicate that untreated MIL‐53 (Al) exhibits negligible resistance switching behavior; however, following hydrochloric acid leaching, it demonstrates excellent retention (103 cycles), longtime durability (103 s), and a favorable ON/OFF ratio (≈25) under bias conditions. Furthermore, under suitable pulse stimulation, the MIL‐53 (Al)‐based memristor successfully emulates biological synaptic behaviors, including excitatory postsynaptic current and paired pulse facilitation. This research presents a novel approach for enhancing the resistive switching performance of MOF‐based memristors.

Semi-interpenetrating polybenzimidazole membrane containing polymeric ionic liquid with high power density and enhanced proton conductivity for fuel cells

In phosphoric acid (PA)-doped polybenzimidazole (PBI) membranes designed for high-temperature proton exchange membranes (HT-PEMs), increasing the PA doping is essential. Yet, excessive PA doping causes a decline in mechanical strength, which in turn affects the cell performance. We utilize a strategy that integrates elevated PA absorption, increased mechanical strength, and enhanced PA retention. An azide-type ionic liquid (IL) containing double bonds was synthesized and crosslinked with PBI via free radical polymerization reaction. In addition, the IL can also self-polymerize to form long-chain polymeric ionic liquid (PIL). Together, the two structures together form a semi-interpenetrating polymer network (sIPN) system, which has good mechanical properties. The synthesized alkaline ionic liquid can absorb and retain a large amount of PA through acid-base interactions and inter-ionic interactions. Consequently, the proton conductivity of the amino-type polybenzimidazole (AmPBI)-polymeric ionic liquid (PIL)-30 (where 30 stands for the wt% of IL) membrane in an anhydrous environment at 180 °C reached 138.2 mS cm−1. After PA retention test at 160 °C/0 % relative humidity (RH) for 240 h, the proton conductivity reached 99.4 mS cm−1 at 180 °C. The AmPBI-PIL-10 membrane exhibited a significant power density of 635.4 mW cm−2 at 160 °C. The AmPBI-PIL-X composite membranes exhibited exceptional performance.

Composite membrane comprised of SnO2 nanoparticles loaded intercrosslinked network of Polyvinylalcohol and Chitosan for proton transfer membrane fuel cells

ABSTRACT In this work, an inter-crosslinked network membrane of polyvinyl alcohol (PVA) and chitosan (CS) and SnO2 nanocparticle-incorporated nanocomposite membranes of PVA and CS (PVA/CS/SnO2) having enhanced proton conductivity have been fabricated by the solvent-casting method. SnO2 nanoparticles are synthesized using a sol–gel method, and their crystalline nature, morphology and particle size are examined using X-ray diffraction analysis, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM), and the characteristics of the membranes such as proton conductivity (PC), swelling ratio (SR), porosity, water uptake (WU), oxidative stability (OS), ion exchange capacity (IEC), and other common physiochemical characteristics were also assessed for both the bare and SnO2 nanoparticles loaded PVA/CS films. At room temperature (RT), the highest IEC rate of 0.94 mmol g−1 and proton conductivity value of 6.3 × 10−3 S cm−1 for PVA/CS/SnO2 were observed when 3 weight percent SnO2 nanoparticles were added to PVA/CS. Additionally, the PVA/CS/SnO2 compsoite membrane loaded with 3 wt% SnO2 NPs, at 80°C for 10 hours, showed outstanding OS with 12.3% degradation towards the Fenton reagent under anhydrous conditions. As this work combines the upgrading of commodity polymers, like PVA, to be employed in fuel cell devices, the nanocomposite membranes created in this work showed notable properties that may find a large place in the future fuel cell industry.

Hydrocarbon-based composite membranes containing sulfonated Poly(arylene thioether sulfone)-grafted 2D crown ether framework coordinated with cerium ions for PEMFC applications

We propose a novel strategy to develop sulfonated poly(arylene ether sulfone) (SPAES) composite membranes that can simultaneously improve the physicochemical stability and proton conductivity of hydrocarbon-based membranes for PEMFC applications. This strategy involves the use of a sulfonated poly(arylene thioether sulfone)-grafted 2D crown ether framework coordinated with cerium3+ ions (SATS–C2O–Ce) as a promising filler material. SATS-C2O, a highly sulfonated polymer-grafted 2D framework containing crown ether holes in its skeletal structure, was prepared via self-condensation using halogenated phloroglucinol as a multifunctional building unit to form C2O, followed by condensation using SATS to graft the sulfonated polymer onto its edge. Ce3+ ions were directly coordinated within the crown ether holes of SATS-C2O via a simple doping process using aqueous Ce solution. The SPAES composite membranes containing SATS–C2O–Ce (SPAES/SATS–C2O–Ce) exhibited exceptional dimensional stability and mechanical toughness. The remarkable chemical stability of SPAES/SATS–C2O–Ce compared to that of pristine SPAES and SPAES/Ce (containing the same amount of Ce3+ ions but without SATS-C2O) was attributed to the well-dispersed state of Ce3+ ions within the SPAES matrix. Furthermore, the enhanced proton conductivity of SPAES/SATS–C2O–Ce surpassed those of pristine SPAES, SPAES/C2O, and SPAES/Ce by the formation of additional proton-conducting channels provided by the sulfonic acid groups of SATS–C2O–Ce, along with the improved water uptake capability of SPAES.

Research Progress in Enhancing Proton Conductivity of Sulfonated Aromatic Polymers with ZIFs for Fuel Cell Applications

The escalating global temperatures and their adverse effects underscore the growing imperative for the widespread adoption of clean fuels, notably hydrogen. Proton Exchange Membrane Fuel Cells (PEMFC) emerge as a pivotal green energy technology, facilitating electricity and water generation. The optimization of PEMFC efficiency hinges on the judicious selection and fabrication of polymer membranes. Within innovative materials, Zeolitic Imidazolate Frameworks (ZIFs) represent a novel subclass within the expansive family of Metal-Organic Frameworks (MOFs). ZIFs exhibit promising potential in PEMFCs, owing to their distinctive properties such as a substantial contact surface, inherent porosity, and a sizable pore volume. This comprehensive review delves into composite membranes featuring ZIFs, shedding light on their chemical and thermal attributes. Additionally, the exploration extends to elucidating the diverse applications of ZIF compounds, accompanied by an in-depth discussion of selected chemical and thermal properties inherent to ZIF compounds. Incorporating ZIFs into various polymers yielded intriguing outcomes, demonstrating a notable enhancement in proton conductivity. The compilation of this review aims to provide researchers with foundational insights into the realm of ZIFs, serving as a valuable resource for future investigations and advancements in the field.

Polymeric ionic liquids and piperidinium synergistically improve proton conductivity and acid retention of polybenzimidazole-based proton exchange membranes

Amino-type polybenzimidazole is prepared, then ionic liquid with three nitrogen positive sites ([CTDTr]Br3) is polymerized into polymeric ionic liquids (PILs) by in-situ radical polymerization, and AmPBI-CTDTr-Px membranes were prepared by piperidinium (PPd) and [CTDTr]Br3 combination to cross-linked with AmPBI. Following treatment with KOH and phosphoric acid (PA), the ion pairs (N+ - H2PO4-) generated in the composite membrane system can enhance proton conductivity and facilitate proton transport. The AmPBI-CTDTr-Px membranes shown exceptional PA retention as a result of the alkaline properties of both [CTDTr]Br3 and PPd, which can engage in acid-base interactions with phosphoric acid. Specifically, the proton conductivity of AmPBI-CTDTr-P5 at 180 °C is 129.7 mS cm-1, which is 2.52 times that of pure membranes. Acid retention of AmPBI-CTDTr-P5 at 80 °C/40% RH and 160 °C are 64.4% and 84%.

High-performance PVdF-HFP/PEG-IL composites: The combined effects of PEG and ionic liquid on proton conductivity and dielectric characteristics

This study explores the influence of varying polyethylene glycol (PEG) concentrations on the properties of PVdF-HFP/PEG-IL polymer composites through comprehensive characterization techniques, including FTIR, SEM, TGA, DMA, XRD and the detailed assessments of proton conductivity, dielectric properties, and relaxation dynamics. In terms of conductivity, the addition of PEG markedly improves proton conductivity. The PVdF-HFP/PEG40-IL composite exhibits the highest conductivity, reaching 1.96 × 10⁻2 S/m at 1 MHz and 300 K, and increasing to 4.27 × 10⁻2 S/m at 420 K. Dielectric properties show that the dielectric constant (ε′) increases with PEG content at low frequencies but decreases at higher frequencies due to reduced ionic polarization. Notably, PVdF-HFP/PEG40-IL achieves a dielectric constant of 3.39 × 106 at 20 Hz, which decreases to 30.34 at 1 MHz. Dielectric loss (ε'') also rises with temperature, with PVdF-HFP/PEG40-IL demonstrating the highest dielectric loss, indicative of superior proton conduction and polarization capabilities. Relaxation dynamics, as evidenced by tanδ, reveal that relaxation time significantly decreases with both increased PEG content and temperature, dropping from 1.06 × 10⁻4 s to 2 × 10⁻6 s as PEG concentration increases from 10 % to 40 %. This reduction in relaxation time correlates with enhanced proton conductivity and faster dipole relaxation, indicating PEG effect as a plasticizer that reduces polymer viscosity and improves ion transport. In conclusion, incorporating PEG into PVdF-HFP-IL composites leads to substantial improvements in proton conductivity, dielectric properties, and relaxation dynamics. The results highlight the crucial role of PEG in optimizing the performance of polymer electrolyte composites, making them effective candidates for advanced energy storage and conversion applications.

Potential of kaolin as filler in Nafion composite membranes for PEM fuel cells

Nafion is one of the polymer materials used as a polymer exchange membrane (PEM) in fuel cells due to its high proton conductivity, chemical stability, and fuel cell performance. However, Nafion membranes still have notable disadvantages, such as decreased proton conductivity at high temperatures and low humidity. One of the methods applied to overcome these limitations is to add inorganic compounds to the Nafion matrix. In this study, kaolin, a hygroscopic clay, was incorporated into Nafion for the first time to enhance proton conductivity of the membrane. Kaolin-doped composite membranes (5 %, 10 %, and 15 % kaolin by weight) were produced through the solution casting method and analyzed using various characterization techniques. The synthesized membranes exhibited significantly higher water uptake, lower swelling, higher proton conductivity, and better mechanical properties compared to recast Nafion. Among all composite membranes, Nafion-Kaolin-15 demonstrated a proton conductivity of 0.330 S/cm, which is a remarkable enhancement of 1.43 times compared to recast Nafion. These findings revealed the potential of kaolin-doped Nafion membranes for future applications in PEMFCs.

Regulating Molecular Interactions in Polybenzimidazole Membrane for Efficient Vanadium Redox Flow Battery.

The tightly bonded structure of polybenzimidazole (PBI) membrane is the origin of its poor proton conductivity, which severely hinders achieving a cost-effective membrane for vanadium redox flow battery (VRFB). It desires a strategy to relax the membrane structure to significantly improve the proton conductivity and maintain its structure stability. Therefore, this work proposes a novel strategy through regulating molecular interactions within PBI membrane to loosen up the structure of PBI membrane and dramatically enhance the proton conductivity. The interactions in PBI membrane are switched by DMSO/water and acid through sequentially treating membrane with these solutions. The efficient PBI membrane prepared using this strategy demonstrates an outstanding performance for VRFB, with the proton conductivity enhanced by 3850 % (from 1.9 to 76.3 mS cm-1), and VRFB achieves a high energy efficiency of 80.5 % under 200 mA cm-2. More importantly, this work shed lights on the structure-property relationship of PBI membrane, and the mechanism in enhancing proton conductivity is unraveled, which is of great significance for the development of VRFB membranes.

Synergistic effects of liquid phase sintering and B-site substitution to enhance proton conductivity of BaZr0.1Ce0.7Y0.1Yb0.1O3-δ for protonic ceramic fuel cell

This paper is dedicated to improving the sintering and conductivity of BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) by adding ZnO–CuO dual-sintering aids. The synergistic effects of liquid-sintering of Zn and B-site substitution of Cu on the sinterability and proton conductivity of BZCYYb are systematically investigated. X-ray diffraction (XRD) analysis of BZCYYb after addition of ZnO–CuO (BZCYYb-Zn-Cu) confirms the complete perovskite phase formation without any secondary phase. The substitution of Ce4+ (0.87 Å) with Zn2+ (0.74 Å) or Cu2+ (0.73 Å) induces a shift in XRD diffraction peak to higher angle due to a decrease in lattice constant. Energy dispersive X-ray spectroscopy analysis indicate a distinct distribution of Zn primarily at the grain boundaries, while Cu is predominantly located within the grains of BZCYYb-Zn-Cu. The addition of ZnO–CuO into BZCYYb results in a denser microstructure with larger average grain size. Furthermore, the substitution of Ce4+ by Cu2+ increases the concentration of oxygen vacancies and reduces activation energy. For BZCYYb-Zn-Cu, the proton conductivity reaches 4.52 × 10−2 S/cm at 750 °C, approximately 3 times higher than that of BZCYYb. This enhancement can be attributed to the synergistic effects of larger average grain size resulting from liquid phase sintering of Zn, low active energy, and high concentration of oxygen vacancies arising from Cu B-site substitution. BZCYYb-Zn-Cu is used as the electrolyte for anode support SOFC, and the single cell exhibits remarkable electrochemical performance and excellent stability in H2 fuel. This research establishes a crucial theoretical foundation for the preparation and performance evaluation for large-size protonic ceramic cell.

Superior proton conductivity of amino acid-modified UiO-66-(COOH)2 embedded in chitosan: Mechanistic insights into the acid-base interactions

We focus on optimizing acid-base interactions and hydrogen bonding networks to achieve enhanced proton conductivity under low relative humidity (RH) and high temperature. By functionalizing UiO-66-(COOH)2 with glutamic acid (Glu) and lysine (Lys), we generate Glu-UiO-66-(COOH)2 and Lys-UiO-66-(COOH)2. These modified materials are subsequently incorporated into chitosan (CS) to produce the composites Glu-UiO-66-(COOH)2@CS and Lys-UiO-66-(COOH)2@CS. The successful incorporation of amino acids and cross-linking between -COOH and -NH2 groups in the composites, confirmed by FTIR and PXRD analyses, significantly enhances the structural integrity and durability by strengthening the network, and reducing polymer chain mobility. Proton conductivity assessments reveal that Lys-UiO-66-(COOH)2@CS-7 exhibits a remarkable conductivity of 0.022 S/cm at 100 % RH and 363 K, outperforming Glu-UiO-66-(COOH)2@CS-7. The lower activation energy (Ea) of 0.28 eV for Lys-UiO-66-(COOH)2@CS-7, compared to 0.336 eV for Glu-UiO-66-(COOH)2@CS-7, highlights the significant improvement in intramolecular acid-base interactions and hydrogen bonding. Furthermore, Lys-UiO-66-(COOH)2@CS-7 maintains notable proton conductivity at 43 % RH, with an Ea of 0.216 eV, demonstrating its efficacy in low-humidity conditions. These findings underscore the profound impact of amino acid modifications and cross-linking on proton conductivity by reinforcing acid-base interactions, hydrogen bonding networks, and proton transfer efficiency.

Cross-Linking of Bromo-Pillar[5]arenes and Sulfonated Poly(Aryl Ether Ketone Sulfone) Enhances Proton Conductivity of Membranes at Low Ion Exchange Capacity

Cross-Linking of Bromo-Pillar[5]arenes and Sulfonated Poly(Aryl Ether Ketone Sulfone) Enhances Proton Conductivity of Membranes at Low Ion Exchange Capacity

Cross-linked proton exchange membrane covalently bonded with silicotungstic acid for enhanced proton conductivity

Proton exchange membranes with cross-linked structures often showed excellent mechanical and chemical stability, but their water absorption and proton conductivity were restricted. This study reported a convenient and efficient thermal cross-linking reaction of sulfonic acid groups and benzene rings using dimethyl sulfoxide and sulfolane mixed solvents to prepare the membrane. To further illustrate, phenoxyphenyl-attached silicotungstic acid (POP-SiWA) was incorporated in the sulfonated poly(ether ether ketone) membrane and covalently bonded with the polymer by thermal cross-linking reaction. The immobilization ratio for the membranes prepared with 10∼30 wt% POP-SiWA addition was 88.0–63.7%. The modified membranes exhibited high hydrophilicity and improved proton conductivity under hydrated or low relative humidity conditions due to the strong acidity and water-retaining properties of silicotungstic acid. Specifically, the proton conductivity of the modified membrane with 30 wt% POP-SiWA reached 212 mS/cm. It exhibited a fuel cell power density of 629 mW/cm2 at 80 °C and 100% relative humidity, which were 1.90 and 2.67 times higher than the pristine membrane.

Dual-Template-Directed Zero-Dimensional Bismuth Chlorides: Structures, Luminescence, Photoinduced Chromism, and Enhanced Proton Conductivity.

Zero-dimensional (0D) hybrid organic-inorganic bismuth halides have attracted immense scientific interest as promising candidates for lead-free materials. Here, by using a typical solvothermal method, two mixed-cation-phase 0D hybrid bismuth chlorides of [HPDA][H2PDA]BiCl6 (1) and [Hbzim][H2PA]BiCl6 (2) (PDA = bis(4-pyridyl)amine, bzim = benzimidazole, PA = 2-picolylamine) have been assembled based on a series of organic amine guests. Both compounds exhibit interesting photoluminescence phenomena, in which compound 1 exhibits a double emission property of blue fluorescence and yellow-green phosphorescence simultaneously, while compound 2 exhibits wide-band yellow-green emission under visible light excitation. The luminescence mechanism is explained by experiments and theoretical calculations. In view of the fact that halometallate units and the conjugated nitrogen heterocyclic systems can act as electron donors and electron acceptors, respectively, both compounds exhibit free radical-driven photochromism induced by electron transfer under xenon lamp irradiation at room temperature. In addition, benefiting from abundant hydrogen bond networks in structures, the two compounds show significant temperature-dependent proton conduction behavior in the range of 298-343 K, and the proton conductivity of both compounds is significantly improved after light irradiation. Our study demonstrates two novel hybrid mixed-cation-phase 0D hybrid bismuth halides with photoluminescence, photochromism, and photomodulated proton conduction properties, which enriches the dual-template-directed metal halide system and provides a feasible scheme for the synthesis of photoresponsive smart materials.

Sodium-Poor, Hydroxyl-Rich, Defective Na2Ti3O7 Prepared by γ-Irradiation and Its Enhanced Proton Conductivity.

The use of γ-irradiation to tailor the physicochemical properties of materials is not widely applied to layered alkali metal oxides. Herein, we show that γ-irradiation (up to 400 kGy) of Na2Ti3O7 leads to a sodium-poor, hydroxyl-rich analogue where the layered structure, plate-like morphology, and textural properties are preserved. The deintercalation of sodium ions modifies the Ti-O bond lengths and expands the unit cell; the latter is supported by density functional theory (DFT) calculations. 23Na solid-state NMR suggests the transport of the symmetric, 7-fold Na2 sites to an intermediate environment, which is closer to the asymmetric, 9-fold Na1 sites. An 8 wt % mass loss (1.4 mol water/mol titanate) is observed, indicating an increased concentration of protons/hydroxyls. These hydroxyl groups (i.e., lattice protons) possess higher thermal stability than solely surface-adsorbed ones in the nonirradiated sample. At 200-400 kGy, the proton conduction (50 °C and ∼70% RH) of ∼10-6 S·cm-1 is 1 order of magnitude larger than that in the nonirradiated sample; the relaxation time decreases from 30 to 2-6 μs with γ-irradiation. The γ-dose dependence of dielectric loss is also present and analyzed using the Jonscher universal power law, indicating the low-frequency dispersion behavior characteristics of high charge densities.

Structural Landscape and Proton Conduction of Lanthanide 5-(Dihydroxyphosphoryl)isophthalates.

Metal phosphonate-carboxylate compounds represent a promising class of materials for proton conduction applications. This study investigates the structural, thermal, and proton conduction properties of three groups of lanthanide-based compounds derived from 5-(dihydroxyphosphoryl)isophthalic acid (PiPhtA). The crystal structures, solved ab initio from X-ray powder diffraction data, reveal that groups Ln-I, Ln[O3P-C6H3(COO)(COOH)(H2O)2] (Ln = La, Pr), and Ln-II, Ln2{[O3P-C6H3(COO)(COOH)]2(H2O)4}·2H2O (Ln = La, Pr, Eu), exhibit three-dimensional frameworks, while group Ln-III, Ln[O3P-C6H3(COO)(COOH)(H2O)] (Ln = Yb), adopts a layered structure with unbonded carboxylic groups oriented toward the interlayer region. All compounds feature carboxylic groups and coordinating water molecules. Impedance measurements demonstrate that these materials exhibit water-mediated proton conductivity, initially following a vehicle-type proton-transfer mechanism. Upon exposure to ammonia vapors from a 14 or 28% aqueous solution, compounds from groups II and III adsorb ammonia and water, leading to an enhancement in proton conductivity consistent with a Grotthuss-type proton-transfer mechanism. Notably, group II of the studied compounds undergoes the formation of a new expanded phase through the internal reaction of carboxylic groups with ammonia, coexisting with the as-synthesized phase. This postsynthetic modification results in a significant increase in proton conductivity, from approximately ∼5 × 10-6 to ∼10-4 S·cm-1 at 80 °C and 95% relative humidity (RH), attributed to a mixed intrinsic/extrinsic contribution. Remarkably, the NH3(28%)-exposed Yb-III compound achieves an enhancement in proton conductivity, reaching ∼ 5 × 10-3 S·cm-1 at 80 °C and 95% RH, primarily through an extrinsic contribution.

Rare-earth induced peroxo-phosphotungstates: Enhanced proton conductivity in corresponding membranes

Rare-earth induced peroxo-phosphotungstates: Enhanced proton conductivity in corresponding membranes

Covalent triazine frameworks crosslinked microporous polymer membranes with fast and selective ion transport for ultra-stable vanadium redox flow batteries

The vanadium redox flow batteries (VRFBs) are an essential pathway to long-duration energy storage with the merits of power and energy decoupling, long lifetime and safety. However, low coulombic efficiency stemming from vanadium crossover across the membrane together with notable ohmic loss originated from low proton conductivity of the membrane still limits high performance operation of the VRFBs. Herein, we proposed 2,2′-bipyridine-based covalent triazine frameworks (bipCTF) crosslinked sulfonated-poly (4,4′-diphenylether-5,5′-bibenzimidazole) (SOPBI) (bipCTF/SP-100) for use as the membrane in VRFBs, which synergistically prevents vanadium crossover and enhances proton conductivity. By delicately tuning the sulfonation degree and properly incorporate bipCTF, the bipCTF/SP-100 membrane is successfully synthesized based on OPBI polymers, which delivers a reduced area resistance of 0.3 Ω cm2 and a low VO2+ permeability of 19.05 × 10−9 cm2 s−1, affording an excellent trade-off between proton conductivity and ion selectivity. Theoretical calculation further corroborates that the high proton conductivity of bipCTF/SP-100 is attributed to the ionic channels formed by bipCTF, while the superior ion selectivity is assigned to protonated imidazole and pyridine. Benefiting from microporous bipCTF/SP-100 membrane, the VRFB exhibits a high CE of 99.8 % and an excellent EE of 78.3 % at 250 mA cm−2 and meanwhile yields a high capacity retention of 94.8 % after 200 cycles at 200 mA cm−2, which shows enormous potential for high power density operation of the VRFBs.

Advanced hybrid membrane constructed with silicon carbide, graphene oxide and functionalized silicon carbide for vanadium permeability, proton conductivity to battery and fuel cell applications

The energy sector is currently exploring eco-friendly energy conversion and storage devices, as an alternative to traditional fossil fuel devices. A unique hybrid proton exchange membrane is developed for proton exchange membrane fuel cells (PEMFC) and vanadium redox flow battery (VRFB) application. Polymeric nanocomposite membranes are effective for the selective and controlled transportation of ions between the electrodes. This study utilizes various modifiers such as GO, SGO, SPES, and SiC, to modify the PES polymer matrix. Analysis of the functional groups confirmed the presence of modifiers and hydroxyl groups on the nanocomposite membrane. Additionally, the use of Field Emission Scanning Electron Microscopy (FESEM) validated the existence of honeycomb and sponge-like voids as well as the surface morphology on the membrane surface. The incorporation of modifiers into the nanocomposite membrane matrix serves as a reliable barrier for the transport of vanadium ions, leading to a significant reduction in vanadium ion permeability across the membrane. The mechanical properties and ion exchange capacity of nanocomposite membranes are enhanced, while the permeability of VO2+ decreases compared to that of the bare PES membrane. The enhancement of proton conductivity is further achieved with the utilization of modifiers in PES polymer. As compared to bare PES membrane, PES/SPES + SGO (5%) exhibits less than half the permeability for vanadium, and PES/SiC shows 44.03 % elongation means twice of bare PES membrane.