Article
Chemistry, Physical
L. Padilla Urbina, J. Liu, N. Semagina, M. Secanell
Summary: Inkjet printing is a feasible technique for the fabrication of electrode in unitized regenerative fuel cells (URFCs) and the study of optimal ionomer and catalyst loading. A physical mixture of Pt, IrOx, and Nafion ionomer was directly inkjet printed on a Nafion membrane to create bifunctional oxygen electrodes with varying loading for a URFC. The results show that the optimal electrode requires low ionomer loading and significantly less IrOx catalyst than platinum.
JOURNAL OF POWER SOURCES
(2023)
Article
Green & Sustainable Science & Technology
Hang Guo, Jia Song, Fang Ye, M. A. Chong Fang
Summary: The oxygen side flow channel structures have a significant influence on the dynamic response of relevant parameters during the operation mode switching procedures of a unitized regenerative fuel cell. The study compared the influence of eight oxygen-side channels on the mode switching process and found that the required time for parameters to reach a stable state in the fuel cell mode is longer when using orientational flow channels. Additionally, different flow channel structures affect the time required to stabilize each parameter during mode switching, but do not change the characteristics of the stable state mode.
Review
Environmental Studies
Teresa Maria Gulotta, Roberta Salomone, Francesco Lanuzza, Giuseppe Saija, Giovanni Mondello, Giuseppe Ioppolo
Summary: Unitized Regenerative Fuel Cell (URFC) is a promising green hydrogen technology for clean energy production, but further research is needed to make it more attractive across various sectors. The analysis of Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) studies on URFCs using proton exchange membrane (PEM) devices reveals varying environmental and economic impacts, highlighting the need for increased transparency and harmonization in these assessments.
ENVIRONMENTAL IMPACT ASSESSMENT REVIEW
(2022)
Article
Thermodynamics
Hang Guo, Jia Song, Fang Ye, Chong Fang Ma
Summary: The gas flow channels inside unitized regenerative fuel cells have significant effects on parameter changing behaviors during mode switching. Previous studies have not investigated the transportation behaviors inside a cell constructed with streamlined channels in detail. In this study, a two-dimensional, transient model coupling non-isothermal characteristics is used to analyze the changing characteristics of the cell with a streamlined channel and its impact on the working states. The simulation results show that reducing the depth of the oxygen-side channels increases the current density output and reduces the stabilizing time needed for the working state.
INTERNATIONAL JOURNAL OF GREEN ENERGY
(2023)
Review
Chemistry, Physical
Shiyi Wang, Adam Z. Weber, Xiong Peng
Summary: This review highlights recent progress on high-performing PEM-URFCs, focusing on electrode engineering, key components, and operating approaches that consider realistic conditions. The study also discusses key components of a membrane electrode assembly (MEA), including the catalyst layer, diffusion media, and membrane, which require different optimization strategies.
CURRENT OPINION IN ELECTROCHEMISTRY
(2023)
Article
Thermodynamics
Qing Guo, Hang Guo, Fang Ye, Chong Fang Ma
Summary: In this study, three different channel structures of unitized regenerative fuel cells are designed and manufactured based on numerical simulation. The output electricity performance test of the single cell in different modes is realized, providing effective verification data for the two-phase model verification. The results show that different channel configurations result in various performance behaviors during different procedures of the cell.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Chemistry, Physical
Noor ul Hassan, Prabhu Ganesan, Aaron A. Lando, William E. Mustain, Hector R. Colon-Mercado
Summary: Anion exchange membrane unitized regenerative fuel cells (AEM-URFCs) are a promising technology for energy storage and electricity production, but their efficiency is limited by the kinetics of the bifunctional oxygen electrode. This study advances the efficiency of the oxygen electrode by using new electrocatalysts, achieving high round trip efficiency and the highest performance reported to date in AEM-URFCs.
JOURNAL OF POWER SOURCES
(2022)
Article
Thermodynamics
Jia Song, Hang Guo, Fang Ye, Chong Fang Ma
Summary: This paper discusses the influence of operating conditions on two-phase species distributions in a unitized regenerative fuel cell, using a two-dimensional transient numerical model. The results show that reducing the operating voltage and increasing the gas inlet velocity can improve the cell performance. Providing the reaction gas with the same concentration as the fuel cell mode in advance has little impact on the parameter values and currents after stabilization.
INTERNATIONAL JOURNAL OF GREEN ENERGY
(2023)
Article
Chemistry, Physical
Ahyoun Lim, Ju Sung Lee, Suji Lee, So Young Lee, Hyoung-juhn Kim, Sung Jong Yoo, Jong Hyun Jang, Yung-Eun Sung, Hyun S. Park
Summary: In this study, the water flux of the anode and cathode electrodes is systematically controlled by manipulating the relative humidity of the supplied gas and altering the selection of the electrode in amphiphilic membrane electrode assembly. By investigating the operation factors of URFC, a high round trip efficiency of 51 % (@ 0.4 A cm(-2)) was achieved with only 0.65 mg((Pt+Ir)) cm(-2) of the noble catalyst.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Article
Thermodynamics
Rui Jiao Yu, Hang Guo, Hao Chen, Fang Ye
Summary: Mass transfer between cathode catalyst layer and gas diffusion layer reflects the reactant content entering into the catalyst layer and the production content discharged. Heat transfer inside the fuel cell is closely related to the electrochemical reaction and affects the reaction rate. Investigating heat and mass transfer at the interface helps understand the influence of various parameters on cell performance. The study found that more platinum or carbon loading enhances heat and mass transfer, but excessive loading affects cell durability. The porosity of the gas diffusion layer and the ionomer content in the catalyst layer have different effects on cell performance under different voltages.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Engineering, Chemical
Longsheng Zhao, Kang Shang, Jiyao Wang, Zhenqian Chen
Summary: The effect of thermal conductivity changes in three coordinate directions of porous electrodes on the performance of proton exchange membrane fuel cells was investigated. The results showed that thermal conductivity in the Z-direction had the greatest impact, while conductivity in the X- and Y-directions had a negligible effect. Increasing thermal conductivity improved the performance of the fuel cell, but the improvement decreased as conductivity increased due to the thinness of the electrode. The Z-direction conductivity played a significant role in temperature distribution and water-carrying capacity of the fuel cell.
Article
Electrochemistry
Md. Masud Rana, Palanisamy Rajkumar, Beom-Soo Kang, Gyungse Park, Ho-Jung Sun, So Yeon Kim, Hong-Ki Lee, Joongpyo Shim
Summary: In this study, the effect of different membrane treatment processes on the performance of anion exchange membrane-unitized regenerative fuel cells (AEM-URFCs) was investigated. By replacing bromide ions (Br-) with hydroxyl ions (OH-), cell performance was greatly enhanced. The concentration of OH- ions in the KOH solution had a significant impact on Br- ion replacement. The MEA treated with 1.0 M KOH in a mixture of isopropyl alcohol (IPA) and deionized water (H2O) (25/75 vol%) exhibited the lowest Br- ion content and highest current densities in both fuel cell and water electrolyzer modes.
JOURNAL OF APPLIED ELECTROCHEMISTRY
(2023)
Article
Energy & Fuels
Jun Shen, Changqing Du, Fuwu Yan, Ben Chen, Zhengkai Tu
Summary: The presence of side blockages enhances the concentration of O-2 in the flow field, thus improving the convective mass transfer coefficient and performance of the PEMFC. Flow channels with side blockages have lower maximum temperature, more uniform temperature distribution, and increased heat transfer compared to straight channels. The installation of side blockages enhances the synergistic effect of heat and mass transfer processes under turbulence conditions.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2022)
Article
Thermodynamics
Ping'an Li, Diankai Qiu, Linfa Peng, Shuiyun Shen, Xinmin Lai
Summary: In this study, an experimental measurement protocol for the degradation of Unitized Regenerative Fuel Cell (URFC) was established, confirming that the degradation mainly occurs in the water electrolysis mode. Carbon corrosion on the MPL side of the GDL was found to be the main cause of URFC degradation, leading to a reduction in water transport capacity and an increase in CCM proton conduction resistance.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Chemistry, Physical
Qing Guo, Hang Guo, Fang Ye, Lei Xing, Chong Fang Ma
Summary: This study establishes a model of unitized regenerative fuel cell and investigates the impact of cell voltages and operating temperatures on the distribution of thermal fluid during the purging process and the discharge of residual liquid water in electrolytic cell mode. The results demonstrate that the purging gas temperature has a significant influence on water flooding, while the operating voltage greatly affects water diffusion.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Thermodynamics
Jia Song, Hang Guo, Fang Ye, Chong Fang Ma
Summary: A two-dimensional, two-phase, non-isothermal, and unsteady state unitized regenerative fuel cell model was established in this study to investigate the effects of various operating conditions on cell performance. Different conditions have different effects on cell performance and parameters. Increasing electrolytic cell voltage can gradually improve cell performance, while increasing water flow rate can speed up stabilization time but slightly reduce cell performance.
INTERNATIONAL JOURNAL OF GREEN ENERGY
(2022)
Article
Thermodynamics
Qing Guo, Hang Guo, Fang Ye, Chong Fang Ma
Summary: This study investigates the importance of water management in unitized regenerative fuel cells for their start-up characteristics and output performance. The complex effects of residual water and liquid water in the purging mode on cell performance are validated through modeling and experiments.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Thermodynamics
Jia Xing Liu, Hang Guo, Fang Ye, Chong Fang Ma
Summary: This paper investigates the electrical performance changes during continuous mode switching between fuel cell and electrolytic modes through experimental research. It is found that the voltage slightly decreases during mode switching, and the two-phase flow phenomenon is similar in different modes. Bubbles are generated and water is consumed in electrolytic mode, while liquid water gathers in the fuel cell mode. The cycle test results show that the voltage of both electrolytic cell and fuel cell decreases periodically, especially under high current density.
INTERNATIONAL JOURNAL OF GREEN ENERGY
(2023)
Article
Green & Sustainable Science & Technology
Hang Guo, Qiang Zhao, Fang Ye
Summary: In this study, a flow field plate with a transparent observation window was used to observe the liquid movement behaviors inside fuel cells from the side. The experimental results showed that the design of oriented-type flow channels affects the generation, movement, and shape of liquid droplets, and higher current densities result in more liquid water generation.
Article
Engineering, Chemical
Gaojian Chen, Weidong Shi, Jin Xuan, Zeljko Penga, Qian Xu, Hang Guo, Huaneng Su, Lei Xing
Summary: The performance of proton exchange membrane fuel cells is significantly affected by the lower local oxygen concentration and more severe water flooding under the rib area compared to the channel area. A novel flow field design with auxiliary channels equipped with through-plane arrayed holes was manufactured using 3D metal printing to improve oxygen concentration and water drainage under the rib. The design improved cell performance at high current density by balancing electric resistance and mass transfer under the rib, and was made possible through the implementation of 3D printing technology.
Article
Electrochemistry
Rui Jiao Yu, Hang Guo, Fang Ye
Summary: In this study, a three-dimensional, non-isothermal, two-phase agglomerate model considering the porosity difference of the gas diffusion layer was established, and numerical simulations were conducted to investigate the influence of different coefficients on the overall cell performance. The results showed that different coefficients have varying effects on the cell characteristics at different voltages.
ELECTROCHIMICA ACTA
(2022)
Article
Energy & Fuels
Hongzhe Zhang, Fang Ye, Hang Guo, Xiaoke Yan
Summary: This study focused on improving thermocouple calibration equipment by using potassium CAHP, demonstrating its ability to provide a stable and uniform temperature field. Through measurements and studies, it was found that CAHP can effectively reduce the impact of heating temperature fluctuations on temperature uniformity in the metering wells.
Article
Energy & Fuels
Hongzhe Zhang, Fang Ye, Hang Guo, Xiaoke Yan
Summary: This paper summarizes previous studies on the application fields of the isothermal performance of heat pipes, the isothermal level of heat pipes used in different fields, and the methods to improve the isothermal performance of heat pipes. It is found that the parameters of the wick have little effect on the temperature uniformity of the heat pipe, while the arrangement of the wick has more influence on the uniformity of the heat pipe. The most suitable charge rate is 15% to 30% of the total inner volume, and the best start-up performance and isothermal performance is at approximately 45 degrees.
Article
Energy & Fuels
Hongzhe Zhang, Fang Ye, Hang Guo, Xiaoke Yan
Summary: In this study, a temperature comparison source based on potassium concentric annular heat pipe was fabricated to replace the metal temperature equalizing block, and the temperature stability and uniformity of different metering wells at different temperatures were experimentally studied.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2022)
Article
Thermodynamics
Hao Chen, Hang Guo, Fang Ye, Chong Fang Ma
Summary: Orientational flow channels with baffles and porous blocks can enhance reactant transportation in proton exchange membrane fuel cells. However, the diffusion and convection processes in this channel structure are still unclear.
INTERNATIONAL JOURNAL OF GREEN ENERGY
(2023)
Article
Chemistry, Physical
Qing Guo, Hang Guo, Fang Ye, Lei Xing, Chong Fang Ma
Summary: This study establishes a model of unitized regenerative fuel cell and investigates the impact of cell voltages and operating temperatures on the distribution of thermal fluid during the purging process and the discharge of residual liquid water in electrolytic cell mode. The results demonstrate that the purging gas temperature has a significant influence on water flooding, while the operating voltage greatly affects water diffusion.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Energy & Fuels
Hang Guo, Qiang Zhao, Fang Ye
Summary: This study monitors the two-phase flow behaviors in a proton exchange membrane fuel cell with orientated-type flow channels through side-view direction, while also recording the changing behaviors of cell performance and temperature. The results show that the orientational flow channel structure facilitates removing liquid droplets and enhances convective heat transfer, although it slightly reduces the electrochemical reaction rates. The observation of liquid water movement, simultaneous measurements of temperature changing behaviors, and current generation processes contribute to a better understanding of the characteristics of fuel cells with orientated-type flow channels.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2022)
Article
Energy & Fuels
Rui Jiao Yu, Hang Guo, Fang Ye, Hao Chen
Summary: This study investigates the effects of structure parameters of gas diffusion layer and catalyst layer on the performance of proton exchange membrane fuel cells. A model and optimization algorithm are used to determine the optimal parameter distribution. The results show that selecting parameters obtained at 0.4 V along the Z-axis can improve cell performance.
Article
Thermodynamics
Jia Nan Qiao, Hang Guo, Hao Chen, Fang Ye
Summary: This paper proposes a staircase flow channel for the oxygen-side flow channel of a unitized regenerative fuel cell and investigates the impact of different step numbers on hydrothermal distribution. The results show that the use of staircase structures can improve oxygen transport, reduce liquid water accumulation, and alleviate oxygen starvation under high current density.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Thermodynamics
Dmitry V. Zaitsev, Valentin V. Belosludtsev, Egor M. Tkachenko, Fang Ye, Hang Guo, Vyacheslav V. Cheverda, Oleg A. Kabov
Summary: This study verifies the methodology of experimental investigation of heat transfer in a flat microchannel and demonstrates the advantages of shear-driven liquid films in terms of critical heat flux.
INTERFACIAL PHENOMENA AND HEAT TRANSFER
(2022)