A model of an irreversible proton exchange membrane （PEM） fuel cell working at steady-state was established, in which overpotenfials, internal currents, and crossover losses were taken into account. The expressions ...A model of an irreversible proton exchange membrane （PEM） fuel cell working at steady-state was established, in which overpotenfials, internal currents, and crossover losses were taken into account. The expressions of some key parameters of the fuel cell were derived from the point of electrochemistry and thermodynamics. Based on the irreversible model of the PEM fuel ceil, the influence of multi-irreversibilities on fuel cell performance were characterized and compared systematically. The general performance characteristic curves were generated. Moreover, when the electrical circuit was dosed with a load in it, the relations between the load resistance and power output density and efficiency were analyzed. The results provide a theoretical basis for both the operation and optimal design of real PEM fuel cells.展开更多
Hydrogen production by proton exchange membrane electrolysis has good fluctuation adaptability,making it suitable for hydrogen production by electrolysis in fluctuating power sources such as wind power.However,current...Hydrogen production by proton exchange membrane electrolysis has good fluctuation adaptability,making it suitable for hydrogen production by electrolysis in fluctuating power sources such as wind power.However,current research on the durability of proton exchange membrane electrolyzers is insufficient.Studying the typical operating conditions of wind power electrolysis for hydrogen production can provide boundary conditions for performance and degradation tests of electrolysis stacks.In this study,the operating condition spectrum of an electrolysis stack degradation test cycle was proposed.Based on the rate of change of the wind farm output power and the time-averaged peak-valley difference,a fluctuation output power sample set was formed.The characteristic quantities that played an important role in the degradation of the electrolysis stack were selected.Dimensionality reduction of the operating data was performed using principal component analysis.Clustering analysis of the data segments was completed using an improved Gaussian mixture clustering algorithm.Taking the annual output power data of wind farms in Northwest China with a sampling rate of 1 min as an example,the cyclic operating condition spectrum of the proton-exchange membrane electrolysis stack degradation test was constructed.After preliminary simulation analysis,the typical operating condition proposed in this paper effectively reflects the impact of the original curve on the performance degradation of the electrolysis stack.This study provides a method for evaluating the degradation characteristics and system efficiency of an electrolysis stack due to fluctuations in renewable energy.展开更多
The characters of proton exchange membranes from sulfonated poly( aryl ether sulfone) s( SPAESs) containing fluorophenyl pendant groups are studied in this paper.Both the water uptake and the water content parameter( ...The characters of proton exchange membranes from sulfonated poly( aryl ether sulfone) s( SPAESs) containing fluorophenyl pendant groups are studied in this paper.Both the water uptake and the water content parameter( λ) of all SPAES membranes increase almost linearly with sulfonation degree( SD)and temperature.After being equilibrated in deionized water,the dimensional change in plane is much less affected by temperature than that in vertical direction.Under all the humidity condition the proton conductivities of these SPAES membranes increase with SD and temperature.A maximus proton conductivity of 0.38 S/cm is attained at 90 ℃ for SPAES-5 with a SD of 99.3% when the membrane is fully hydrated,higher than that of Nafion 115.But the proton conductivities of SPAES membranes decrease dramatically with the relative humidity and all of them are lower and more affected by relative humidity than that of Nafion 115 at relative humidity lower than 100%,which may be due to the cumulative effects of narrower channels with spherical clusters for proton migration,more rigid chains and larger tortuosity of SPAESs.展开更多
Developing an active and stable anode catalyst for the proton exchange membrane water electrolyzer(PEM-WE)is a critical objective to enhance the economic viability of green hydrogen technology.However,the expensive ir...Developing an active and stable anode catalyst for the proton exchange membrane water electrolyzer(PEM-WE)is a critical objective to enhance the economic viability of green hydrogen technology.However,the expensive iridium-based electrocatalyst remains the sole practical material with industrial-level stability for the acidic oxygen evolution reaction(OER)at the anode.Ruthenium-based catalysts have been proposed as more cost-effective alternatives with improved activity,though their stability requires enhancement.The current urgent goal is to reduce costs and noble metal loading of the OER catalyst while maintaining robust activity and stability.In this study,we design a Ru-based OER catalyst incorporating Pb as a supporting element.This electrocatalyst exhibits an OER overpotential of 201 mV at 10 mA·cm^(-2),simultaneously reducing Ru noble metal loading by~40%.Normalization of the electrochemically active surface area unveils improved intrinsic activity compared to the pristine RuO_(2) catalyst.During a practical stability test in a PEM-WE setup,our developed catalyst sustains stable performance over 300 h without notable degradation,underscoring its potential for future applications as a reliable anodic catalyst.展开更多
To analyze the additional cost caused by the performance attenuation of a proton exchange membrane electrolyzer(PEMEL)under the fluctuating input of renewable energy,this study proposes an optimization method for powe...To analyze the additional cost caused by the performance attenuation of a proton exchange membrane electrolyzer(PEMEL)under the fluctuating input of renewable energy,this study proposes an optimization method for power scheduling in hydrogen production systems under the scenario of photovoltaic(PV)electrolysis of water.First,voltage and performance attenuation models of the PEMEL are proposed,and the degradation cost of the electrolyzer under a fluctuating input is considered.Then,the calculation of the investment and operating costs of the hydrogen production system for a typical day is based on the life cycle cost.Finally,a layered power scheduling optimization method is proposed to reasonably distribute the power of the electrolyzer and energy storage system in a hydrogen production system.In the up-layer optimization,the PV power absorbed by the hydrogen production system was optimized using MALTAB+Gurobi.In low-layer optimization,the power allocation between the PEMEL and battery energy storage system(BESS)is optimized using a non-dominated sorting genetic algorithm(NSGA-Ⅱ)combined with the firefly algorithm(FA).A better optimization result,characterized by lower degradation and total costs,was obtained using the method proposed in this study.The improved algorithm can search for a better population and obtain optimization results in fewer iterations.As a calculation example,data from a PV power station in northwest China were used for optimization,and the effectiveness and rationality of the proposed optimization method were verified.展开更多
基金National Natural Science Foundation of China (No. 51078068)Fundamental Research Funds for the Central Universities,China (No. 11D11314)Natural Science Foundation of Shanghai,China (No. 10ZR1401300)
文摘A model of an irreversible proton exchange membrane （PEM） fuel cell working at steady-state was established, in which overpotenfials, internal currents, and crossover losses were taken into account. The expressions of some key parameters of the fuel cell were derived from the point of electrochemistry and thermodynamics. Based on the irreversible model of the PEM fuel ceil, the influence of multi-irreversibilities on fuel cell performance were characterized and compared systematically. The general performance characteristic curves were generated. Moreover, when the electrical circuit was dosed with a load in it, the relations between the load resistance and power output density and efficiency were analyzed. The results provide a theoretical basis for both the operation and optimal design of real PEM fuel cells.
基金supported by the National Key Research and Development Program of China(Materials and Process Basis of Electrolytic Hydrogen Production from Fluctuating Power Sources such as Photovoltaic/Wind Power,No.2021YFB4000100).
文摘Hydrogen production by proton exchange membrane electrolysis has good fluctuation adaptability,making it suitable for hydrogen production by electrolysis in fluctuating power sources such as wind power.However,current research on the durability of proton exchange membrane electrolyzers is insufficient.Studying the typical operating conditions of wind power electrolysis for hydrogen production can provide boundary conditions for performance and degradation tests of electrolysis stacks.In this study,the operating condition spectrum of an electrolysis stack degradation test cycle was proposed.Based on the rate of change of the wind farm output power and the time-averaged peak-valley difference,a fluctuation output power sample set was formed.The characteristic quantities that played an important role in the degradation of the electrolysis stack were selected.Dimensionality reduction of the operating data was performed using principal component analysis.Clustering analysis of the data segments was completed using an improved Gaussian mixture clustering algorithm.Taking the annual output power data of wind farms in Northwest China with a sampling rate of 1 min as an example,the cyclic operating condition spectrum of the proton-exchange membrane electrolysis stack degradation test was constructed.After preliminary simulation analysis,the typical operating condition proposed in this paper effectively reflects the impact of the original curve on the performance degradation of the electrolysis stack.This study provides a method for evaluating the degradation characteristics and system efficiency of an electrolysis stack due to fluctuations in renewable energy.
基金National Natural Science Foundation of China(No.51608056)Open Foundation of National Engineering Laboratory of Highway Maintenance Technology of China(No.kfj140105)+1 种基金General Project Supported by Hunan Province Education Office,China(No.16C0025)Natural Science Foundation of Hunan Province,China(No.2018JJ3537)
文摘The characters of proton exchange membranes from sulfonated poly( aryl ether sulfone) s( SPAESs) containing fluorophenyl pendant groups are studied in this paper.Both the water uptake and the water content parameter( λ) of all SPAES membranes increase almost linearly with sulfonation degree( SD)and temperature.After being equilibrated in deionized water,the dimensional change in plane is much less affected by temperature than that in vertical direction.Under all the humidity condition the proton conductivities of these SPAES membranes increase with SD and temperature.A maximus proton conductivity of 0.38 S/cm is attained at 90 ℃ for SPAES-5 with a SD of 99.3% when the membrane is fully hydrated,higher than that of Nafion 115.But the proton conductivities of SPAES membranes decrease dramatically with the relative humidity and all of them are lower and more affected by relative humidity than that of Nafion 115 at relative humidity lower than 100%,which may be due to the cumulative effects of narrower channels with spherical clusters for proton migration,more rigid chains and larger tortuosity of SPAESs.
基金supported by the Robert A.Welch Foundation(No.C-2051-20230405)the David and Lucile Packard Foundation(No.2020-71371)the Alfred P.Sloan Foundation(No.FG-2021-15638).
文摘Developing an active and stable anode catalyst for the proton exchange membrane water electrolyzer(PEM-WE)is a critical objective to enhance the economic viability of green hydrogen technology.However,the expensive iridium-based electrocatalyst remains the sole practical material with industrial-level stability for the acidic oxygen evolution reaction(OER)at the anode.Ruthenium-based catalysts have been proposed as more cost-effective alternatives with improved activity,though their stability requires enhancement.The current urgent goal is to reduce costs and noble metal loading of the OER catalyst while maintaining robust activity and stability.In this study,we design a Ru-based OER catalyst incorporating Pb as a supporting element.This electrocatalyst exhibits an OER overpotential of 201 mV at 10 mA·cm^(-2),simultaneously reducing Ru noble metal loading by~40%.Normalization of the electrochemically active surface area unveils improved intrinsic activity compared to the pristine RuO_(2) catalyst.During a practical stability test in a PEM-WE setup,our developed catalyst sustains stable performance over 300 h without notable degradation,underscoring its potential for future applications as a reliable anodic catalyst.
基金supported by the National Key Research and Development Program of China(Materials and Process Basis of Electrolytic Hydrogen Production from Fluctuating Power Sources such as Photovoltaic/Wind Power,No.2021YFB4000100)。
文摘To analyze the additional cost caused by the performance attenuation of a proton exchange membrane electrolyzer(PEMEL)under the fluctuating input of renewable energy,this study proposes an optimization method for power scheduling in hydrogen production systems under the scenario of photovoltaic(PV)electrolysis of water.First,voltage and performance attenuation models of the PEMEL are proposed,and the degradation cost of the electrolyzer under a fluctuating input is considered.Then,the calculation of the investment and operating costs of the hydrogen production system for a typical day is based on the life cycle cost.Finally,a layered power scheduling optimization method is proposed to reasonably distribute the power of the electrolyzer and energy storage system in a hydrogen production system.In the up-layer optimization,the PV power absorbed by the hydrogen production system was optimized using MALTAB+Gurobi.In low-layer optimization,the power allocation between the PEMEL and battery energy storage system(BESS)is optimized using a non-dominated sorting genetic algorithm(NSGA-Ⅱ)combined with the firefly algorithm(FA).A better optimization result,characterized by lower degradation and total costs,was obtained using the method proposed in this study.The improved algorithm can search for a better population and obtain optimization results in fewer iterations.As a calculation example,data from a PV power station in northwest China were used for optimization,and the effectiveness and rationality of the proposed optimization method were verified.
