Polymer Electrolyte Research Articles

Study on Bonding Characteristics of Aluminum Alloy Treated by Plasma Electrolytic Oxidation Process and Polymer Resin Bonded by Direct Injection Molding

Aluminum alloy and polymer resin hybrid bonding technology is essential for lightweight mobile phone frames and automotive components. Recently, there has been extensive research on a method of bonding metals and polymer resins by treating the metal surface and then direct injection molding. However, this method requires separate surface treatment of the aluminum alloy after bonding to enhance its corrosion resistance. This paper studies the use of Plasma Electrolytic Oxidation, one of the surface treatment methods for aluminum, to achieve the bonding of aluminum and polymer resin in a single surface treatment step while ensuring high corrosion resistance. We conducted research to investigate optimal conditions by adjusting the process variables of Plasma Electrolytic Oxidation, in order to achieve integration with the polymer resin and measure the bonding strength and corrosion resistance. The surface characteristics of each Plasma Electrolytic Oxidation condition were analyzed using scanning electron microscopy and atomic force microscope equipment, while the bonding strength was measured using universal testing machine equipment. The corrosion characteristics were evaluated by measuring the corrosion resistance in a saltwater solution.

Techno-economic optimization and working fluid selection of a biogas-based dual-loop bi-evaporator ejector cooling cycle involving power-to-hydrogen and water facilities

Biogas-fueled decentralized energy systems featuring gas turbines emerge as pivotal players in the quest for more adaptable and eco-friendly energy solutions. This study presents the design of a cutting-edge multigeneration system that harnesses the potential of a gas turbine coupled with ejector-driven dual-loop bi-evaporator technology, reverse osmosis desalination, proton exchange membrane electrolysis, and an organic Rankine cycle. The research encompasses an extensive sensitivity analysis and deploys a genetic algorithm-based optimization technique. Through meticulous Optimization, the system achieves remarkable outcomes, including electricity generation, cooling capacity, heating capacity, desalinated water production, and hydrogen yield, measured at 957.3 kW, 231.4 kW, 272.3 kW, 7.336 kg/s, and 0.99 kg/h, respectively. Notably, this performance surpasses the base case by 2% and 8.9%, yielding exergy efficiency and total unit cost improvements of 33.3% and 16.4 $/GJ. Among the critical decisions made was selecting an organic working fluid for the organic Rankine cycle. Through rigorous evaluation, isobutene emerged as the optimal choice, demonstrating significantly improved output power compared to alternatives. Isobutane as the working fluid led to a substantial increase in overall exergy efficiency and a resultant total unit cost of 18.06 $/GJ, accompanied by an impressive 23.48% exergy efficiency.

Research on In-Plane Thermal Conductivity Detection of Fuel Cell Bipolar Plates Based on Laser Thermography

Research on In-Plane Thermal Conductivity Detection of Fuel Cell Bipolar Plates Based on Laser Thermography

Polybenzimidazole dispersed polymer coated nanowires as efficient electrolytes for proton exchange membrane fuel cells

In this study, polymer-coated anisotropic inorganic nanowires dispersed in PBI matrix were introduced to construct 1D proton conducting channels within PBI. Ionic-liquid and solvothermal methods were used for the synthesis of ZrO2 and W18O49 NWs, which were coated with PVPA and PDDA polymers to increase their proton conductivity. Our results showed that, prepared membranes have amorphous nature due to the dominating presence of PBI. SEM analysis revealed the average thickness of membrane of about 36 µm. TG/DTA analysis detected lower weight loss of W18O49 NWs (total 2.8%) compared to ZrO2 NWs (18%). Proton conductivity analysis showed that, PDDA/W18O49 NWs possess relatively 4 times higher proton conductivity (4×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \ imes $$\\end{document}10−4 Scm−1) compared to PDDA/ZrO2 NWs (1×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \ imes $$\\end{document}10−4 Scm−1) at 80 ℃. In addition, PDDA-coated W18O49 NWs dispersed PBI membranes showed the highest fuel cell current density (1.2 A/cm2) and power density (215 mW/cm2) at 150 ℃ after 24 h which is nearly 2.5 times higher than pure PBI membrane. In addition, they exhibited the lowest in-situ proton resistance of about (0.47 Ω) compared with that of pure PBI membrane (0.8 Ω). Our results are introducing new concepts towards the development of thin and efficient polymer electrolyte membranes for PEM fuel cells.

Conducting Carbon Black Nano‐Filler Doped Polymer Electrolyte for Electrochemical Application

AbstractThis study provides a development of polymer electrolytes with an emphasis on their use in electrochemical devices. In present study we develop a new conducting carbon black (CB) powder dispersed into polyethylene oxide (PEO) polymer electrolyte using solution cast method. Various characterization techniques such as Impedance spectroscopy technique (EIS), Fourier transform infrared spectroscopy (FTIR), and Window stability (LSV) Linear sweep voltammetry has been studied in detail. The maximum ionic conductivity polymer electrolyte was at 0.05 wt%. of CB with σ value 1.20×10−5 S/cm. Finally the prepared CB dispersed polymer electrolyte using maximum conductivity sample is sandwiched between electrodes to fabricate an Electric double layer capacitor and Dye‐sensitized solar cell which show highest electrical capacity value of 68.5 F/gm at 5 mV/s respectively and 2.97 % efficiency shown by solar cell at 1 sun condition.

Nest-Scheme RuIrLa Nanocrystals by NP-to-NP Oriented Assembly: Coherent Strain Fields-Driven Band Structure Splitting for Efficient Acidic Water Oxidation.

Atomic substructure engineering provides new opportunities for the designing newly and efficient catalysts with diverse atom ensembles, trimmed electron bands, and way-out coordination environments, creating unique contributing to concertedly catalyze water oxidation, which is of great significance for proton exchange membrane water electrolysis (PEMWE). Herein, nest-scheme RuIrLa nanocrystals with dense coherent interfaces as built-in substructures are firstly fabricated by using commercial ZnO particles as acid-removable templates, through a La-stabilized coherent epitaxial growth of nanoparticles (NPs). The obtained nests exhibit a low overpotential of 198mV at 10mA cm-2, and the RuIrLa||Pt/C module equipped in PEMWE operates stably at a cell voltage potential of 1.69V at 100mA cm-2 in 0.5M H2SO4 for 55h, which is far beyond the current IrO2||Pt/C. Within the nests, the position at the interface shows high tensile/compressive strain, significantly reducing the OER activation energy. More importantly, the La termination-stabilized coherent interfaces within the nests creates a unique self-healing process for the outstanding long-term stability. This work provides a promising substructure engineering to develop efficient catalysts with abundant substructures, such as coherent interfaces, dislocations, or grain boundaries, thereby realizing concerted improvement of activity and durability toward water oxidation.

Impact of the flow-field distribution channel cross-section geometry on PEM fuel cell performance: Stamped vs. milled channel

Polymer electrolyte membrane fuel cells (PEM FCs) represent an essential part of the emerging hydrogen economy. Metallic bipolar plates (BPs) allow high speed and capacity production using established industrial technologies, like mechanical stamping. Stamping, however, leads to different cross-sectional shapes of flow-field (FF) channels as compared to milled or compression-moulded bipolar plates. The impact of these changes on the resulting fuel cell performance is not yet fully understood. This study employs an experimentally validated three-dimensional, isothermal, steady-state, continuum-mechanics based mathematical model to gain a deeper insight into this issue and to identify optimal stamped BP channel cross-sectional shapes for parallel and serpentine FF. The uniformity of the local distribution of the physico-chemical quantities and the resulting load curves are analysed. The results obtained confirm that stamped BPs with channels of the trapezoidal cross-section are a viable alternative to the traditional milled or moulded BPs with channels of the rectangular cross-section. The observed differences in performance of FC with stamped and milled channels can be mitigated by optimization of the channel cross-section geometry parameters. As an optimal rib width 0.4 mm and an optimal channel ground width 1 mm for milled and 0.2 mm for stamped BPs are suggested.

Compliant Solid Polymer Electrolytes (SPEs) for Enhanced Anode-Electrolyte Interfacial Stability in All-Solid-State Lithium–Metal Batteries (LMBs)

Compliant Solid Polymer Electrolytes (SPEs) for Enhanced Anode-Electrolyte Interfacial Stability in All-Solid-State Lithium–Metal Batteries (LMBs)

Analysis of Power-to-gas-to-X systems with metal hydride storage based on coupled electrochemical and thermodynamic simulation

Power-to-gas-to-X systems consisting of photovoltaic cells, proton-exchange membrane electrolysis, hydrogen storage based on metal hydrides, proton-exchange membrane fuel cells and buffer batteries could be used to meet heat and electricity demands of homes, businesses, or small districts. The actual size of the individual components and their interplay have to be optimized for the technical and economic feasibility of the overall system. A simulation-based optimization workflow would be a suitable way to accomplish this task, but there are hardly any tools that can simultaneously simulate power, fluid and heat flows of such systems and efficiently perform their optimization. In this paper, a multiphysical energy system simulation and optimization tool is introduced which models electrochemical and thermodynamic processes simultaneously, including modern equations of state and an own numerical solver for the arising differential–algebraic system of equations, and provides new methods for the calibration of parameters of the metal hydride storage, proton-exchange membrane electrolyzer and fuel cell as well as a metamodel-based approach for sizing optimization. As a demonstrator for the novel tool, a simulation model of a hydrogen lab is successfully set up based on experimental results. The novel tool is able to extract polarization and jump curves of the fuel cell, determine a first temperature and pressure dependency of the efficiency of the electrolysis coupled with the metal hydride storage and speed up sizing optimization through metamodeling by a factor 262.1 at 4.9% and 32.7 at 3.3% accuracy.

Study of Mass Transport in the Anode of a Proton Exchange Membrane Fuel Cell with a New Hydrogen Flow‐Rate Modulation Technique

AbstractHydrogen transport in the anode of a proton‐exchange membrane fuel cell (PEMFC) has been studied with a modulation technique relating the hydrogen flow‐rate ( ) and the faradaic current ( ), called Current‐modulated Hydrogen flow‐rate Spectroscopy (CH2S). A simple analytical expression for the transfer function, H(jω)=n F / , is provided, showing a skewed semicircle in Nyquist representation (−H'' vs. H'), extending from H’=0 to H’=1, and with the maximum frequency at ωmax=2.33(DH2 /Li2), where DH2 is the effective hydrogen diffusivity and Li the thickness of the anode gas diffusion layer (GDL). The expression for CH2S is also calculated with an existing reversible chemical reaction in the GDL. Experimental results under different operation conditions show two transport processes limiting the anode reaction, one attributed to molecular diffusion through the partially saturated GDL, and the other to the microporous layer (MPL), or its interfaces with GDL or with the catalyst layer (CL). CH2S provides the hydrogen diffusivities (DH2,i) associated to each process under the different conditions. Current density decreases slightly the diffusivity of the GDL, while it becomes activated in the MPL; using two GDLs in the anode improves both GDL and MPL diffusivities; humidification decreases the diffusivity in both, GDL and MPL; finally, a superhydrophobic anodic CL prepared by electrospray improves hydrogen diffusivity in GDL and MPL.

An in-situ polymerization strategy for gel polymer electrolyte Si||Ni-rich lithium-ion batteries

Coupling the Si-based anodes with nickel-rich LiNixMnyCo1−x−yO2 cathodes (x ≥ 0.8) in the energy-dense cell prototype suffers from the mechanical instability of the Li-Si alloys, cathode collapse upon the high-voltage cycling, as well as the severe leakage current at elevated temperatures. More seriously, the cathode-to-anode cross-talk effect of transitional metal aggravates the depletion of the active Li reservoir. To reconcile the cation utilization degree, stress dissipation, and extreme temperature tolerance of the Si-based anode||NMC prototype, we propose a gel polymer electrolyte to reinforce the mechanical integrity of Si anode and chelate with the transitional cations towards the stabilized interfacial property. As coupling the conformal gel polymer electrolyte encapsulation with the spatial arranged Si anode and NMC811 cathode, the 2.7 Ah pouch-format cell could achieve the high energy density of 325.9 Wh kg−1 (based on the whole pouch cell), 88.7% capacity retention for 2000 cycles, self-extinguish property as well as a wide temperature tolerance. Therefore, this proposed polymerization strategy provides a leap toward the secured Li batteries.

Innovative heat management method and metaheuristic algorithm optimized power supply-demand balance for PEMFC-ASHP-CHP system

The evolution of distributed building energy systems fuels the growing demand for sustainable energy solutions. In this paper, Proton Exchange Membrane Fuel Cell (PEMFC) and Air Source Heat Pump (ASHP) were integrated to form PEMFC-ASHP-CHP systems in three combination methods, i.e., Direct Combination (DC), Parallel Combination (PC), Series Combination (SC). And compared the energy management strategies and power balance of the system. To further improve reliability and flexibility, a diversion PEMFC-ASHP-CHP system was proposed by combining PC and SC's system advantages. Additionally, an iterative algorithm addressed the mismatch between power supply and demand. An empirical formula was proposed to improve iterative convergence speed for practical control situations. The coefficients were optimized using six metaheuristic algorithms, and the outcomes were summarized into an optimized operational plane to enhance the system control response speed further. The results show that the PC method performs better than DC and SC. It achieves a power consumption reduction of 52.8% and a COP improvement of 111.4% compared with the ASHP system. Meanwhile, the diversion system can more effectively utilize waste heat from the PEMFC and further improve the system's performance. The Queuing Search Algorithm (QSA) demonstrates superior accuracy for coefficient optimization. By using the established empirical formula, the convergence speeds of global and local iterative methods are improved by 26.10% and 41.78%, respectively, compared to the direct iterative algorithm. Ultimately, the optimized operational plane can achieve a maximum 37.16% hydrogen consumption reduction compared to the unoptimized system.

In situ and Operando Characterisation in the Preferential Oxidation of Carbon Monoxide over Base Metal Oxide Catalysts: A Review

AbstractPolymer electrolyte membrane fuel cells (PEMFCs) are the core technology of the steadily growing hydrogen (H2) economy as they can convert chemical energy, in the form of H2, to electrical energy. If the H2 is derived from (green) hydrocarbons, via steam reforming and the water‐gas‐shift reaction, then it would contain small amounts of carbon monoxide (CO, 0.5–2 %), among other gases. CO poisons the platinum‐based anode catalyst in the PEMFC, and the current recommendation is to decrease its concentration to below 0.01 % (or 100 ppm) in the H2‐rich PEMFC feed. The preferential oxidation of CO (CO‐PrOx) is a promising strategy for decreasing the CO concentration, and base metal oxide catalysts have shown great potential in this regard. However, such catalysts tend to undergo physicochemical changes that cause undesirable catalytic activity and selectivity changes. This review discusses the different base metal oxide catalysts that have been evaluated in CO‐PrOx, while paying special attention to the various in situ and operando techniques that have been used to monitor the physicochemical changes of base metal oxides during operation. We conclude the review by highlighting the recent and possible future attempts of circumventing the undesired physicochemical changes of base metal oxides during CO‐PrOx.

Effect of Fluorine Segments in Fluoropolymer matrix on the Properties of Gel Polymer Electrolytes

Polymer quasi‐solid electrolytes have been paid widely attention in account of their outstanding advantages in safety, flexibility, viscoelasticity and film formation. Fluoropolymer is used as matrix of gel electrolytes not only has high electrochemical stability, but also facilitates the dissociation of lithium salts owning to the strong electron‐absorbing C‐F groups, which makes it a very promising choice for the further development of gel electrolytes. Due to the different sites of C‐F bonds, their activity is also diverse, which results in the difference of the mobility of lithium ions and the LiF composition of SEI film on the surface of lithium metal anode. As a result, distinct fluorine‐containing gel polymer electrolytes are prepared by in‐situ polymerization of two different monomers, HFMA and TFMA. Compared with ‐CF3 on terminal group in TFMA, the gel electrolyte polymerized with HFMA whose C‐F group with stronger electronegativity is at the intermediate carbon site, as polymer matrix has better performance. The ionic conductivity achieves 7.02×10−3 S cm−1 at room temperature, and the assembled batteries have a capacity retention rate of 91% after 200 cycles of 1 C. Our research has laid a solid theoretical foundation for the further development of quasi‐solid electrolyte.

Self‐Supporting Solid Electrolyte Based on Supramolecular Interaction for Stable Li Metal Batteries

AbstractLi metal batteries based on solid polymer electrolytes offer the benefits of high energy density and safety, as well as extended cycling life, making them an excellent candidate for the next‐generation battery system. However, current solid polymer electrolytes still suffer from low ion conductivity and Li+ transfer number, which seriously restricts its practical application. Herein, a self‐supporting composite solid polymer electrolyte was prepared, where phenolic resin rich in hydroxyl groups (BR) and polyethylene oxide (PEO) are mixed evenly and poured onto a cellulose membrane in one step. In such an electrolyte, PEO and BR combine to form intermolecular hydrogen bonds, lowering the crystallinity of PEO and increasing the Li+ transfer number. Lastly, the obtained solid electrolytes exhibited a high ion conductivity (1.1×10−4 S cm−1) and Li+ transfer number (0.53), as well as improved electrochemical window. Consequently, Li || Li symmetrical cells can run stably for more than 700 h at 0.1 mA cm−2/0.25 mAh cm−2. And full cells with LiFePO4 cathode can also demonstrate high discharge capacity of 152.12 mAh g−1 and rate performance. We believe that such a design based on supramolecular interaction offer a new avenue to advanced solid polymer electrolytes.

Development of solid-state hybrid capacitor using carbon nanotube film as current collector

Abstract Structural energy-storage devices are receiving considerable attention because they can simultaneously store electrical energy and provide structural support, thereby offering high volumetric and gravimetric capacities. Although carbon fiber–based materials have been the most popular choice for current collectors, their conductivity and specific surface area are relatively low; this limits the ability to load other active materials on to the current collector. Carbon nanotube (CNT) fiber is a promising alternative for lightweight structural materials because it has a density of less than 1 g/cm3 as well as high strength and electrical conductivity. In this study, we produced a light, strong, and porous CNT film (CNTF) via direct spinning for use as a current collector. The CNTF exhibited a high specific strength compared with Al foil. We also created an activated carbon–lithium titanium oxide hybrid capacitor with the CNTF current collector, which achieved a capacity similar to that of a capacitor having an Al current collector. Furthermore, a planar pouch cell created using a solid polymer electrolyte achieved a capacity of 74.1 mAh/g, which is comparable to that of coin cells. Thus, our findings highlight the feasibility of CNTF as a material for current collectors and provide a foundation to develop manufacturing processes for structural batteries.

An enhanced transfer learning based on addernet and deep domain confusion for prognostic of proton exchange membrane fuel cells

Proton exchange membrane fuel cells (PEMFCs) offer high energy conversion rate and low pollution, while low durability of PEMFCs hinder the further development. Accurately predicting degradation trends and remaining useful life (RUL) are crucial to timely detecting problem and improving PEMFCs durability. In this paper, an enhanced transfer learning (Add-TL) based on adder network (AdderNet) and deep domain confusion is proposed for the prediction of PEMFCs. To reinforce the ability of extracting key features from extensive data, AdderNet with attention mechanism is applied. Furthermore, the fused deep domain confusion employs existing data to achieve higher prediction accuracy. The experimental results demonstrate that Add-TL outperforms other classical methods in predicting degradation trend, the optimal adjusted R-square (R2) values for the two datasets are 0.99879 and 0.99906, respectively. When Add-TL is applied to RUL prediction, the accuracy scores for two datasets reach 0.995, which further validating the applicability of Add-TL in PEMFCs prediction.

Exploring Recent Developments in Graphene-Based Cathode Materials for Fuel Cell Applications: A Comprehensive Overview.

Fuel cells are at the forefront of modern energy research, with graphene-based materials emerging as key enhancers of performance. This overview explores recent advancements in graphene-based cathode materials for fuel cell applications. Graphene's large surface area and excellent electrical conductivity and mechanical strength make it ideal for use in different solid oxide fuel cells (SOFCs) as well as proton exchange membrane fuel cells (PEMFCs). This review covers various forms of graphene, including graphene oxide (GO), reduced graphene oxide (rGO), and doped graphene, highlighting their unique attributes and catalytic contributions. It also examines the effects of structural modifications, doping, and functional group integrations on the electrochemical properties and durability of graphene-based cathodes. Additionally, we address the thermal stability challenges of graphene derivatives at high SOFC operating temperatures, suggesting potential solutions and future research directions. This analysis underscores the transformative potential of graphene-based materials in advancing fuel cell technology, aiming for more efficient, cost-effective, and durable energy systems.

In situ synthesis of cross-linking gel polymer electrolyte for lithium metal batteries

AbstractThe room temperature ionic conductivity of polyethylene oxide (PEO)-based polymer electrolytes is low, the electrochemical window is narrow, and the mechanical strength is relatively poor. In this work, a cross-linking gel-based solid composite polymer electrolyte (CG-SCPE) was synthesized by introducing electrochemically stable carbonate-based functional groups. The synthesized CG-SCPE presents excellent tensile strength (26 MPa) and a wide electrochemical stability window (> 4.5 V vs. Li/Li+). Meanwhile, the in situ polymerization method induced by thermal heating resulted in good compatibility between electrodes/electrolytes. In addition, the assembled LiNi0.5Co0.2Mn0.3O2/CG-SCPE/Li battery exhibited satisfactory electrochemical performance. Therefore, the gel polymer electrolyte CG-SCPE with cross-linking network provides the possibility for future application of safe and high-performance solid-state lithium metal batteries. The results indicate that the introduction of cross-linking framework can simultaneously improve the mechanical strength, thermal stability, and electrochemical performance of solid polymer electrolyte.

Dumbbell-Shaped, Block-Graft Copolymer with Aligned Domains for High-Performance Hydrocarbon Polymer Electrolyte Membranes.

Given the environmental concerns surrounding fluoromaterials, the use of high-cost perfluorinated sulfonic acids (PFSAs) in fuel cells and water electrolysis contradicts the pursuit of clean energy systems. Herein, we present a fluorine-free dumbbell-shaped block-graft copolymer, derived from the cost-effective triblock copolymer, poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS), for polymer electrolyte membranes (PEMs). This unique polymer shape led to the alignment of the hydrophobic-hydrophilic domains along a preferred orientation, resulting in the construction of interconnected proton channels across the membrane. A bicontinuous network allowed efficient proton transport with reduced tortuosity, leading to an exceptional ionic conductivity (249 mS cm-1 at 80 °C and 90 % relative humidity (RH)), despite a low ion exchange capacity (IEC; 1.41). Furthermore, membrane electrode assembly (MEA) prepared with our membrane exhibited stable performance over a period of 150 h at 80 °C and 30 % RH. This study demonstrates a novel polymer structure design and highlights a promising outlook for hydrocarbon PEMs as alternatives to PFSAs.