Polymer Electrolyte Research Articles

Green hydrogen prospects in Peninsular Malaysia: a techno-economic analysis via Monte Carlo simulations

According to Malaysia's National Energy Transition Roadmap, hydrogen is a critical component of the country's energy transition. However, there is a scarcity of hydrogen studies for Peninsular Malaysian states, which limits discussions on green hydrogen production. This study employs a Monte Carlo model to assess the economic and technical factors influencing the success of green hydrogen in Peninsular Malaysia. The study focuses on three target years: 2023, 2030, and 2050, representing various stages of technological development and market adoption. The levelized cost of hydrogen (LCOH) of a 1-MW Proton Exchange Membrane (PEM) electrolyzer system ranges from $5.39 to $10.97 per kg in 2023, highlighting early-stage challenges and uncertainties. A 6-MW PEM electrolyzer system could achieve an LCOH of $3.50 to $4.72 per kg by 2030, indicating better prospects. Because of technological advancements and cost reductions, a 20-MW PEM electrolyzer system could achieve an LCOH of $3.12 to $3.64 per kg in 2050. The findings indicate that the northern regions of Peninsular Malaysia have consistently low LCOH values due to favorable geographical conditions. Due to minor variations in solar capacity factors, uncertainty distributions in LCOH remain stable across different regions. Some states may face increased uncertainty, emphasizing the need for additional policy support mechanisms to mitigate risks associated with green hydrogen investments. The sensitivity analysis shows that key cost drivers are shifting, with early-stage electrolyzer investments dominating in 2023 and electricity prices becoming more important in 2030 and 2050. Future research could focus on optimizing green hydrogen systems for areas with underdeveloped green hydrogen industries. This study contributes to informed discussions about green hydrogen production by emphasizing the importance of tailored strategies that consider local conditions and highlighting the role of Peninsular Malaysia in the energy transition.

Enhancing ionic conductivity and controlling lithium dendrite growth via ferroelectric ceramic Bi4Ti3O12

BackgroundSolid polymer electrolytes (SPEs) have gained numerous research interest in the field of lithium metal batteries. Solid polymer electrolytes have improved safety compared to liquid electrolytes. Despite this, their low ionic conductivity remains a major barrier to practical applications. To overcome the challenge of low ionic conductivity in SPEs, our study introduces a novel approach that integrates ferroelectric ceramics with polymer solid electrolytes. MethodsWe used a one-step molten salt method to synthesize Bi4Ti3O12 (BIT), combined with a poly (vinylidene difluoride) matrix to form the composite solid-state electrolyte. Through various electrochemical characterizations and COMSOL Multiphysics simulations, we discovered that the ferroelectric properties of BIT significantly increase the dissociation of lithium salts, leading to a greater concentration of mobile lithium ions and more efficient ion transport. Significant findingsThis electrolyte showed a remarkable improvement in lithium-ion conductivity, reaching a value of 8.5 × 10−4 S cm−1 at room temperature. Batteries made with these composite electrolytes demonstrate superior cycling stability, the capacity retention rates for LFP/SPEs/Li cells remain high, reaching 95 % even after 1,000 cycles at room temperature (25 °C). These findings highlight the promising applications of ferroelectric ceramics in solid-state batteries.

Building Flame-Retardant Polymer Electrolytes via Microcapsule Technology for Stable Lithium Batteries.

Flame retardants could improve the safety properties of lithium batteries (LBs) with the sacrifice of electrochemical performance due to parasitic reactions. To concur with this, we designed thermal-response clothes for hexachlorophosphazene (HCP) additives by the microcapsule technique with urea-formaldehyde (UF) resin as the shell. HCP@UF combines with polyacrylonitrile (PAN) by hydrogen bonds successfully to form PAN-HCP@UF as the flame-retardant solid polymer electrolyte. The hydrogen bonds ensure excellent mechanical properties of the polymer electrolyte. The multiscale free radical-annihilating agent HCP effectively eliminates hydrogen free radicals of electrolytes under high temperature, showing excellent flame retardation. During the operation of the battery, functional groups on the UF resin act as active sites to promote the migration of lithium ions, while the internal HCP is protected from electrochemical reaction. With 25% HCP@UF addition, the limiting oxygen index of the PAN-HCP@UF increases to 28% and the Li+ transfer number up to 0.80. By UF protection, the initial capacity retention rate of the Li||LFP battery that assembles with PAN-HCP@UF is 88.8% after 500 cycles at 0.5 C. Thus, the microcapsule-encapsulated approach is deemed to provide an innovative strategy to prepare high-safety solid-state LB with a stable long cycle life.

Substrate-Free Gas Diffusion Layer Based on a Nonsolvent-Induced Phase Inversion Approach for High-Performance Proton Exchange Membrane Fuel Cells

Substrate-Free Gas Diffusion Layer Based on a Nonsolvent-Induced Phase Inversion Approach for High-Performance Proton Exchange Membrane Fuel Cells

Durable and Active Nitrogen‐Coordinated Iron Single‐Atom Catalyst for Proton Exchange Membrane Fuel Cells Through Carbon Encapsulation

Durable and Active Nitrogen‐Coordinated Iron Single‐Atom Catalyst for Proton Exchange Membrane Fuel Cells Through Carbon Encapsulation

Sensitivity analysis and optimization of operating conditions of proton exchange membrane fuel cell

Sensitivity analysis and optimization of operating conditions of proton exchange membrane fuel cell

Multiscale study of reactive transport and multiphase heat transfer processes in catalyst layers of proton exchange membrane fuel cells

Improving the performance of proton exchange membrane fuel cells (PEMFCs) requires deep understanding of the reactive transport processes inside the catalyst layers (CLs). In this study, a particle-overlapping model is developed for accurately describing the hierarchical structures and oxygen reactive transport processes in CLs. The analytical solutions derived from this model indicate that carbon particle overlap increases ionomer thickness, reduces specific surface areas of ionomer and carbon, and further intensifies the local oxygen transport resistance (Rother). The relationship between Rother and roughness factor predicted by the model in the range of 800-1600 s m-1 agrees well with the experiments. Then, a multiscale model is developed by coupling the particle-overlapping model with cell-scale models, which is validated by comparing with the polarization curves and local current density distribution obtained in experiments. The relative error of local current density distribution is below 15% in the ohmic polarization region. Finally, the multiscale model is employed to explore effects of CL structural parameters including Pt loading, I/C, ionomer coverage and carbon particle radius on the cell performance as well as the phase-change-induced (PCI) flow and capillary-driven (CD) flow in CL. The result demonstrates that the CL structural parameters have significant effects on the cell performance as well as the PCI and CD flows. Optimizing the CL structure can increase the current density and further enhance the heat-pipe effect within the CL, leading to overall higher PCI and CD rates. The maximum increase of PCI and CD rates can exceed 145%. Besides, the enhanced heat-pipe effect causes the reverse flow regions of PCI and CD near the CL/PEM interface, which can occupy about 30% of the CL. The multiscale model significantly contributes to a deep understanding of reactive transport and multiphase heat transfer processes inside PEMFCs.

Thermal enhancement of PEM fuel cell cooling with novel configurations of Tesla valve and hybrid nanofluids: A numerical study

The operating temperature and thermal distribution play a significant role in the appropriate performance of the proton exchange membrane fuel cell (PEMFC). A suitable cell cooling method can guarantee uniform temperature distribution and preservation of membrane water content under harsh conditions in a PEMFC. The compact structure of PEM fuel cells and the size of the cooling system impose a great challenge to achieve a proper design of cooling plate. In this numerical study, four designs of the multi-stage Tesla valve with straight and reverse configuration are proposed to be employed as a cooling channel in which three different hybrid nanofluids such as TiO2–Cu, Al2O3–CuO, and Ag–MgO dispersed in water and Ethylene glycol flow inside the channels. A validated numerical model is developed using a commercial computational fluid dynamics (CFD) code to investigate the effect of inlet temperatures and mass flow rates of cooling fluid and volume fraction of nanoparticles on heat transfer coefficient, pressure drop, index of uniform temperature (IUT), and performance evaluation criteria (PEC). The results demonstrated that the reverse configuration of the Tesla valve (CASE E) experienced outstanding uniform thermal distribution while the heat transfer coefficient increased by 15% in this case compared to the straight-line cooling channel. The Ag–MgO hybrid nanoparticles showed better thermal performance than the two other nanoparticles with a 4% reduction in temperature difference in the cooling plate.

A pore scale model study of mass transfer and electrochemical reaction in cathode catalytic layer of high-temperature polymer electrolyte membrane fuel cells

The mass transfer and related electrochemical reactions in the catalytic layer (CL) are crucial for the performance of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs), but there is a lack of understanding of the optimal phosphoric acid content and Pt/C catalyst loading in the CL. In this work, we investigate the influences of Pt/C catalyst numbers (NPt/C) and phosphoric acid film thickness (δPA) on mass transfer and electrochemical reactions of the cathode CL using a pore-scale model (300 × 300 × 300 nm3). The results reveal that larger NPt/C and δPA can impede oxygen diffusion, while lower NPt/C and δPA lead to fewer reaction active sites and lower conductivity, both of which result in lower current density. Therefore, the balance of three-phase transport is extremely important for CL. There is a 3D volcanic relationship between current density, Pt/C catalysts, and phosphoric acid film. At NPt/C = 200 (7407 per μm3) and δPA = 4 nm (the volume fractions of 37.22 % and 17.87 %), the highest current density can be achieved at a potential of 0.5 V (vs. RHE), which increased with the decrease of potential. This work is valuable for understanding the optimizing the microstructure and three-phase transport pathway of the CL to improve the performance of HT-PEMFCs.

Change of Mechanical Properties of e-PTFE Support by Electrochemical Degradation in Polymer Electrolyte Membrane Fuel Cell

Change of Mechanical Properties of e-PTFE Support by Electrochemical Degradation in Polymer Electrolyte Membrane Fuel Cell

Inhibiting Residual Solvent induced side reactions in Vinylidene Fluoride-based Polymer Electrolytes enables ultra-stable Solid-State Lithium Metal Batteries.

Residual solvents in vinylidene fluoride (VDF)-based solid polymer electrolytes (SPEs) have been recognized as responsible for their high ionic conductivity. However, side reactions by the residual solvents with the lithium (Li) metal induce poor stability, which has been long neglected. This study proposes a strategy to achieve a delicate equilibrium between ion conduction and electrode stability for VDF-based SPEs. Specifically, 2,2,2-Trifluoro-N, N-dimethylacetamide (FDMA) is developed as the non-side reaction solvent for poly(vinylidene fluoride-co-hexafluoropropylene) (PVHF)-based SPEs, achieving both high ionic conductivity and significantly improved electrochemical stability. The developed FDMA solvent fosters the formation of a stable solid electrolyte interphase (SEI) through interface reactions with Li metal, effectively mitigating side reactions and dendrite growth on the Li metal electrode. Consequently, the Li||Li symmetric cells and Li||LiFePO4 cells demonstrate excellent cycling performance, even under limited Li (20μm thick) supply and high-loading cathodes (>10mg cm-2, capacity >1 mAh cm-2) conditions. The stable Li||LiCoO2 cells operation with a cutoff voltage of 4.48V indicates the high-voltage stability of the developed SPE. This study offers valuable insights into developing advanced VDF-based SPEs for enhanced lithium metal battery performance and longevity. This article is protected by copyright. All rights reserved.

Ex-situ Characterization of Nb-Ti Alloy/Pt Coated Stainless Steel Bipolar Plates for Proton Exchange Membrane Fuel Cells

Metallic bipolar plates are crucial for the development of compact and lightweight proton exchange membrane fuel cell stacks; however, most of them encounter durability and conductivity challenges in the fuel cell environment. In this study, Nb-Ti alloy/Pt coatings are deposited on SS316L plates to enhance corrosion resistance, surface wettability, electrical and thermal conductivity, with reduced interfacial contact resistance. Corrosion resistance is assessed by exposing test samples to a 1M H2SO4 acidic environment at 25 °C and 80 °C, respectively, via potentiostatic and potentiodynamic polarization tests. It is found that Nb-Ti alloy/Pt coatings exhibit exceptional stability, with corrosion potential increased by 2.5 (at 25 °C) and 0.5 (at 80 °C) times and corrosion current density reduced by orders of magnitude; and their anti-corrosion performance far exceeds the technical targets set by the US Department of Energy, with a protective efficiency of 99.98 % at both temperatures tested. The coated samples have reduced water affinity, indicated by significantly larger contact angle values compared to the uncoated samples in both pre-and post-corrosion tests. The incorporation of Nb-Ti alloy/Pt coatings on SS316L increases the in-plane electrical conductivity by 42.6 % and thermal conductivity by 3.5 %; surpassing the US Department of Energy's technical targets in these categories as well. At a compaction force of 140 N/cm2, the interfacial contact resistance for the coated samples is about 2.5 times lower than the Department of Energy's requirements. These results indicate the viability of Nb-Ti alloy/Pt coated SS316L bipolar plates for fuel cell applications.

Enhancing Performance and Stability of High-Temperature Proton Exchange Membranes through Multiwalled Carbon Nanotube Incorporation into Self-Cross-Linked Fluorenone-Containing Polybenzimidazole.

Addressing critical challenges in enhancing the oxidative stability and proton conductivity of high-temperature proton exchange membranes (HT-PEMs) is pivotal for their commercial viability. This study uncovers the significant capacity of multiwalled carbon nanotubes (MWNTs) to absorb a substantial amount of phosphoric acid (PA). The investigation focuses on incorporating long-range ordered hollow MWNTs into self-cross-linked fluorenone-containing polybenzimidazole (FPBI) membranes. The absorbed PA within MWNTs and FPBI forms dense PA networks within the membrane, effectively enhancing the proton conductivity. Moreover, the exceptional inertness of MWNTs plays a vital role in reinforcing the oxidation resistance of the composite membranes. The proton conductivity of the 1.5% CNT-FPBI membrane is measured at 0.0817 S cm-1 at 160 °C. Under anhydrous conditions at the same temperature, the power density of the 1.5% CNT-FPBI membrane reaches 831.3 mW cm-2. Notably, the power density remains stable even after 200 h of oxidation testing and 250 h of operational stability in a single cell. The achieved power density and long-term stability of the 1.5% CNT-FPBI membrane surpass the recently reported results. This study introduces a straightforward approach for the systematic design of high-performance and robust composite HT-PEMs for fuel cells.

Optimal parameters identification for PEMFC using autonomous groups particle swarm optimization algorithm

The precise model for Polymer Electrolyte Membrane Fuel Cells (PEMFCs) is vital for simulation, control, and performance analysis of PEMFCs. It is crucial to accurately estimate the model parameters. Over the past decade, the extraction of unknown parameters of PEMFCs model is formulated as optimization problem and several meta-heuristic techniques have emerged to solve this problem. Despite the development of these techniques to tackle the problem, the slow convergence rate and susceptibility to being trapped in local minima are regarded as weaknesses of these methods. Additionally, because the PEMFC model is a nonlinear and complex model, not all optimization algorithms are suitable for solving it. This article introduces a novel approach that utilizes the Autonomous Groups Particle Swarm Optimization (AGPSO) algorithm for extracting precise values for uncertain parameters inherent in PEMFC model of 250Wstack and BCS-500W stack utilized significantly in the literature. The optimization problem's fitness function is formulated as the total squared errors (TSEs) between the voltage datasets measured and estimated. Three different versions of AGPSO algorithm are presented. Statistical analysis is performed on these three versions to assess their robustness, and the most robust version is identified. Furthermore, the performance of the most robust version is extensively tested and analyzed through a complete comparison with recent optimization algorithms findings from the updated state-of-the-art literature such as BO, QOBO, TGA, HHO and ASO. Further, a statistical analysis was carried out that ensured the reliability and robustness of the introduced AGPSO. The results highlight the efficacy and feasibility of AGPSO-based approach across all compared algorithms, demonstrating an enhancement in the accuracy of the PEMFC model. A two-phase sensitivity analysis, conducted through Monte Carlo Simulation (MCS), was employed to assess how variations in optimized parameters affect the objective function (TSEs). Furthermore, the uncertainty in the maximum power reference current is identified.

Operando Scanning Small-/Wide-Angle X-ray Scattering for Polymer Electrolyte Fuel Cells: Investigation of Catalyst Layer Saturation and Membrane Hydration- Capabilities and Challenges.

Polymer electrolyte fuel cells are an essential technology for future local emission-free mobility. One of the critical challenges for thriving commercialization is water management in the cells. We propose small- and wide-angle X-ray scattering as a suitable diagnostic tool to quantify the liquid saturation in the catalyst layer and determine the hydration of the ion-conducting membrane in real operating conditions. The challenges that may occur in operando data collection are described in detail─separation of the anode and cathode, cell alignment to the beam, X-ray radiation damage, and the possibility of membrane swelling. A synergistic development of experimental setup, data acquisition, and data interpretation circumvents the major challenges and leads to practical and reliable insights.

Extracting Accurate Parameters from a Proton Exchange Membrane Fuel Cell Model Using the Differential Evolution Ameliorated Meta-Heuristics Algorithm

The electrochemical proton exchange membrane fuel cell (PEMFC) is an electrical generator that utilizes a chemical reaction mechanism to produce electricity, serving as a sustainable and environmentally friendly energy source. To thoroughly analyze and develop the features and performance of a PEMFC, it is essential to use a precise model that incorporates exact parameters to effectively suit the polarization curve. In addition, parameter extraction plays a crucial role in the simulation analysis, evaluation, optimum control, and fault detection of the proton exchange membrane fuel cell (PEMFC) system. Despite the development of many algorithms for parameter extraction in PEMFC, obtaining accurate and trustworthy results rapidly remains a challenge. This study presents a hybridized algorithm, namely differential evolution ameliorated (DEA) for reliably estimating PEMFC model parameters. To evaluate the proposed DEA-based parameter identification, a comparison analysis with previously published methods is conducted using MATLAB/SimulinkTM (R2016b, MathWorks, Natick, MA, USA) in terms of system correctness and convergence process. The proposed DEA algorithm is tested to extract the parameters of two PEMFC models: SR-12,500 W and 250 W. The sum of the squared errors (SSE) between the experimental and the obtained voltage data is defined as an objective function. The simulation results prove that the suggested DEA algorithm is capable of identifying the optimal PEMFC parameters rapidly and accurately in comparison with other optimization algorithms.

In Situ Integration of a Flame Retardant Quasisolid Gel Polymer Electrolyte with a Si-Based Anode for High-Energy Li-Ion Batteries.

Silicon (Si) stands out as a promising high-capacity anode material for high-energy Li-ion batteries. However, a drastic volume change of Si during cycling leads to the electrode structure collapse and interfacial stability degradation. Herein, a multifunctional quasisolid gel polymer electrolyte (QSGPE) is designed, which is synthesized through the in situ polymerization of methylene bis(acrylamide) with silica-nanoresin composed of nanosilica and a trifunctional cross-linker in cells, leading to the creation of a "breathing" three-dimensional elastic Li-ion conducting framework that seamlessly integrates an electrode, a binder, and an electrolyte. The silicon particles within the anode are encapsulated by buffering the QSGPE after cross-linking polymerization, which synergistically interacts with the existing PAA binder to reinforce the electrode structure and stabilize the interface. In addition, the formation of the LiF- and Li3N-rich SEI layer further improves the interfacial property. The QSGPE demonstrates a wide electrochemical window until 5.5 V, good flame retardancy, high ionic conductivity (1.13 × 10-3 S cm-1), and a Li+ transference number of 0.649. The advanced QSGPE and cell design endow both nano- and submicrosized silicon (smSi) anodes with high initial Coulombic efficiencies over 88.0% and impressive cycling stability up to 600 cycles at 1 A g-1. Furthermore, the NCM811//Si cell achieves capacity retention of ca. 82% after 100 cycles at 0.5 A g-1. This work provides an effective strategy for extending the cycling life of the Si anode and constructing an integrated cell structure by in situ polymerization of the quasisolid gel polymer electrolyte.

Coordinated Control of Proton Exchange Membrane Electrolyzers and Alkaline Electrolyzers for a Wind-to-Hydrogen Islanded Microgrid

In recent years, the development of hydrogen energy has been widely discussed, particularly in combination with renewable energy sources, enabling the production of “green” hydrogen. With the significant increase in wind power generation, a promising solution for obtaining green hydrogen is the development of wind-to-hydrogen (W2H) systems. However, the high proportion of wind power and electrolyzers in a large-scale W2H system will bring about the problem of renewable energy consumption and frequency stability reduction. This paper analyzes the operational characteristics and economic feasibility of mainstream electrolyzers, leading to the proposal of a coordinated hydrogen production scheme involving both a proton exchange membrane (PEM) electrolyzer and an alkaline (ALK) electrolyzer. Subsequently, a coordinated control based on Model Predictive Control (MPC) is proposed for system frequency regulation in a large-scale W2H islanded microgrid. Finally, simulation results demonstrate that the system under PEM/ALK electrolyzers coordinated control not only flexibly accommodates fluctuating wind power but also maintains frequency stability in the face of large disturbances. Compared with the traditional system with all ALK electrolyzers, the frequency deviation of this system is reduced by 25%, the regulation time is shortened by 80%, and the demand for an energy storage system (ESS) is reduced. The result validates the effectiveness of MPC and the benefits of the PEM/ALK electrolyzers coordinated hydrogen production scheme.

Techno-economic assessment of hydrogen as a fuel for internal combustion engines and proton exchange membrane fuel cells on long haul applications

Powertrain energy conversion and management are critical factors in providing affordable and robust solutions for transport decarbonization. Various powertrain technologies are being proposed to reduce the impacts of transportation-related carbon dioxide emissions, such as battery electric, fuel cell, and conventional vehicles running with lower carbon fuels. Specifically for the commercial sector, hydrogen internal combustion engines and fuel cells are being extensively discussed. In this sense, this investigation evaluates the benefits and areas of enhancement for hydrogen internal combustion engines and fuel cells from a techno-economic perspective. Power plant models were developed and validated in GT-Power, and detailed investigations on the energy loss pathways were performed. In addition, the powertrains are included in full longitudinal vehicle models and submitted to different driving cycles, representing homologation and real-world driving conditions, with the intent to understand the effect of the cycles from a global energy management perspective. Finally, the fuel consumption results are used as inputs for a total cost of ownership calculation to determine the economic viability of each powertrain. Overall, fuel cells offered efficient operation across the conditions assessed, with engine-powered powertrains showing reduced efficiencies ranging from 23 % to 63 % depending on the cycle and payload. The limited peak efficiency for the spark-ignited low-pressure hydrogen direct injection engine was a dominant factor for the reduced performance of this platform. Strategies for efficiency improvement are identified that could lead to improved internal combustion engine operation. Despite the limited efficiency benefits of hydrogen internal combustion engines, total cost of ownership calculations show hydrogen internal combustion engines being the most cost-effective solution in the near to medium-term scenario.

Coordinated management of oxygen excess ratio and cathode pressure for PEMFC based on synthesis variable-gain robust predictive control

In this research endeavor, a novel synthesis variable-gain robust model predictive control (SVGRPC) method using the min-max technique with parameter dependent Lyapunov functions is introduced to achieve the desired trajectory tracking of oxygen excess ratio (OER) and cathode pressure in the polymer electrolyte membrane fuel cells (PEMFCs) system. Initially, a simplified control-oriented model of the air supply system is developed and then transformed into a polytopic form to accommodate the inherent uncertainties in the PEMFC. Subsequently, the polytopic model is integrated with the reference trajectory to construct an augmented state-space model for deriving an error state representation. In the framework of robust model predictive control (RPC) utilizing a parameter-dependent Lyapunov function, a series of variable feedback gains are employed to mitigate conservatism. Additionally, the online solution process imposes a significant computational burden, presenting challenges for the real-time implementation of RPC-based control strategy. Therefore, the offline computing is introduced to significantly reduce the computational burden, resulting in the development of the SVGRPC strategy proposed in this paper. Subsequently, the SVGRPC strategy computes explicit linear state-feedback control laws by solving linear matrix inequalities (LMIs) using an offline control algorithm. The effectiveness of the proposed controller is then validated through assessments conducted under three distinct operating conditions of the PEMFC system. The outcomes of this study affirm that the proposed controller improves the requirements of control performance when compared to the online RPC with a quadratic Lyapunov function while significantly alleviating the computational workload.