The widespread commercial adoption of fuel cells requires continued improvements in cost-effectiveness,performance,and durability.A tree-like nitrogen-doped carbon(T-NC)support structure was developed for low-platinum...The widespread commercial adoption of fuel cells requires continued improvements in cost-effectiveness,performance,and durability.A tree-like nitrogen-doped carbon(T-NC)support structure was developed for low-platinum(Pt)loaded fuel cells.Carbon nanotubes serve as the conductive backbone,while ZIF-8-derived carbon,synthesized from 2-methylimidazole zinc salt,forms the branches that provide attachment sites for platinum group metals(PGMs).In cathodes with a Pt loading of 0.1 mgPt/cm^(2),this novel Pt/T-NC electrode exhibited a remarkable 30%reduction in concentration loss at 2.0 A/cm^(2) and a 12.7%increase in peak power density,compared to conventional Pt/C electrodes.Additionally,the corrosion resistance of the electrode was improved.Following 5000 cycles of accelerated durability testing(ADT)for carbon corrosion,the fuel cell retained 50.8%of its original performance,while conventional electrodes retained only 38%.The T-NC structure is broadly applicable for supporting various advanced PGM catalysts.This advancement offers a promising approach to bridge the gap between theoretical catalytic activity and practical output,leading to substantial improvements in both performance and durability of fuel cells.展开更多
Proton exchange membrane fuel cells(PEMFCs)are promising power sources owing to their high-power/energy densities and low pollution emissions.With the increasing demand for electricity for various low-power devices,sm...Proton exchange membrane fuel cells(PEMFCs)are promising power sources owing to their high-power/energy densities and low pollution emissions.With the increasing demand for electricity for various low-power devices,small-scale storage of electricity encountered bottle-neck,which provides new opportunities for PEMFC.Owing to the high specific energy of PEMFCs,the utilization of this technology for small-scale applications has recently attracted significant attention.In recent years,considerable effort has been made to advance PEMFC technology and applications,especially in the small-scale PEMFC commercial market.The current review provides a holistic overview of the cutting-edge developments of small-scale PEMFCs in the transportation,stationary,and portable power generator fields.In particular,we examine current literature on the development of small-scale PEMFCs and discuss the operating complexity of PEMFC systems for different applications.Finally,we provide a forwardlooking perspective on the strategies for small-scale high-specific-power PEMFC systems.展开更多
Proton exchange membrane(PEM)fuel cell has been regarded as a promising approach to the decarbonization and diversification of energy sources.In recent years,durability and cost issues of PEM fuel cells are increasing...Proton exchange membrane(PEM)fuel cell has been regarded as a promising approach to the decarbonization and diversification of energy sources.In recent years,durability and cost issues of PEM fuel cells are increasingly significant with the rapid increase of power density.However,the failure to maintain the cell consistency,as one major cause of the above issue,has attracted little attention.Therefore,this study intends to figure out the underlying cause of cell inconsistency and provide solutions to it from the perspective of multi-physics transport coupled with electrochemical reactions.The PEM fuel cells with electrodes under two compression modes are firstly discussed to fully explain the relationship of cell performance and consistency to electrode structure and multi-physics transport.The result indicates that one main cause of cell inconsistency is the intrinsic conflict between the separated transport and cooperated consumption of oxygen and electron throughout the active area.Then,a mixed-pathway electrode design is proposed to reduce the cell inconsistency by enhancing the mixed transport of oxygen and electron in the electrode.It is found that the mixing of pathways in electrodes at under-rib region is more effective than that at the under-channel region,and can achieve an up to 40%reduction of the cell inconsistency with little(3.3%)sacrificed performance.In addition,all the investigations are implemented based on a self-developed digitalization platform that reconstructs the complex physical–chemical system of PEM fuel cells.The fully observable physical information of the digitalized cells provides strong support to the related analysis.展开更多
The O_(2) permeation barrier across the nanoscale ionomer films on electrocatalysts contributes to a major performance loss of proton exchange membrane(PEM)fuel cells under low Pt loading.Enhancing O_(2) transport thr...The O_(2) permeation barrier across the nanoscale ionomer films on electrocatalysts contributes to a major performance loss of proton exchange membrane(PEM)fuel cells under low Pt loading.Enhancing O_(2) transport through the ionomer films is essential for developing low Pt loading catalyst materials in high-performance PEM fuel cells.This study found that adding an ionic liquid(IL)can effectively mitigate the dense ionomer ultrathin sublayer formed on the Pt surface,which severely hinders O_(2) transport to the catalyst sites.The molecular dynamics simulation results show that adding the IL significantly alters the ionomer ultrathin sublayer structure by inhibiting its tight arrangement of perfluorosulfonic acid chains but scarcely impacts the ultrathin sublayer thickness.Additionally,the IL addition provides a larger free space for O_(2) dissolution in the ultrathin sublayer.Consequently,due to IL molecules’presence,the O_(2) density in the ultrathin sublayer on the Pt surface is improved by an order of magnitude,which will benefit the catalytic efficiency,and the O_(2) permeation flux across the ionomer film is increased by up to 8 times,which will reduce the O_(2) transport loss of the catalyst layer.展开更多
基金supported by the National Natural Science Foundation of China for Distinguished Young Scholars(Grant No.52225604)Jilin Province Science and Technology Development Program,China(Grant No.20230301017ZD).
文摘The widespread commercial adoption of fuel cells requires continued improvements in cost-effectiveness,performance,and durability.A tree-like nitrogen-doped carbon(T-NC)support structure was developed for low-platinum(Pt)loaded fuel cells.Carbon nanotubes serve as the conductive backbone,while ZIF-8-derived carbon,synthesized from 2-methylimidazole zinc salt,forms the branches that provide attachment sites for platinum group metals(PGMs).In cathodes with a Pt loading of 0.1 mgPt/cm^(2),this novel Pt/T-NC electrode exhibited a remarkable 30%reduction in concentration loss at 2.0 A/cm^(2) and a 12.7%increase in peak power density,compared to conventional Pt/C electrodes.Additionally,the corrosion resistance of the electrode was improved.Following 5000 cycles of accelerated durability testing(ADT)for carbon corrosion,the fuel cell retained 50.8%of its original performance,while conventional electrodes retained only 38%.The T-NC structure is broadly applicable for supporting various advanced PGM catalysts.This advancement offers a promising approach to bridge the gap between theoretical catalytic activity and practical output,leading to substantial improvements in both performance and durability of fuel cells.
基金This research is funded by the National Natural Science Foundation of China(No.52106105)the China Postdoctoral Science Foundation(No.2022TQ0231)the Tianjin Research Innovation Project for Postgraduate Students(No.2021YJSB127).
文摘Proton exchange membrane fuel cells(PEMFCs)are promising power sources owing to their high-power/energy densities and low pollution emissions.With the increasing demand for electricity for various low-power devices,small-scale storage of electricity encountered bottle-neck,which provides new opportunities for PEMFC.Owing to the high specific energy of PEMFCs,the utilization of this technology for small-scale applications has recently attracted significant attention.In recent years,considerable effort has been made to advance PEMFC technology and applications,especially in the small-scale PEMFC commercial market.The current review provides a holistic overview of the cutting-edge developments of small-scale PEMFCs in the transportation,stationary,and portable power generator fields.In particular,we examine current literature on the development of small-scale PEMFCs and discuss the operating complexity of PEMFC systems for different applications.Finally,we provide a forwardlooking perspective on the strategies for small-scale high-specific-power PEMFC systems.
基金supported by the National Natural Science Foundation of China(52176196)the Natural Science Foundation of Tianjin(China)for Distinguished Young Scholars(18JCJQJC46700).
文摘Proton exchange membrane(PEM)fuel cell has been regarded as a promising approach to the decarbonization and diversification of energy sources.In recent years,durability and cost issues of PEM fuel cells are increasingly significant with the rapid increase of power density.However,the failure to maintain the cell consistency,as one major cause of the above issue,has attracted little attention.Therefore,this study intends to figure out the underlying cause of cell inconsistency and provide solutions to it from the perspective of multi-physics transport coupled with electrochemical reactions.The PEM fuel cells with electrodes under two compression modes are firstly discussed to fully explain the relationship of cell performance and consistency to electrode structure and multi-physics transport.The result indicates that one main cause of cell inconsistency is the intrinsic conflict between the separated transport and cooperated consumption of oxygen and electron throughout the active area.Then,a mixed-pathway electrode design is proposed to reduce the cell inconsistency by enhancing the mixed transport of oxygen and electron in the electrode.It is found that the mixing of pathways in electrodes at under-rib region is more effective than that at the under-channel region,and can achieve an up to 40%reduction of the cell inconsistency with little(3.3%)sacrificed performance.In addition,all the investigations are implemented based on a self-developed digitalization platform that reconstructs the complex physical–chemical system of PEM fuel cells.The fully observable physical information of the digitalized cells provides strong support to the related analysis.
基金This research was supported by the National Natural Science Foundation of China(Grant No.51921004)the Natural Science Foundation for Outstanding Young Scholars of Tianjin(Grant No.18JCJQJC46700).
文摘The O_(2) permeation barrier across the nanoscale ionomer films on electrocatalysts contributes to a major performance loss of proton exchange membrane(PEM)fuel cells under low Pt loading.Enhancing O_(2) transport through the ionomer films is essential for developing low Pt loading catalyst materials in high-performance PEM fuel cells.This study found that adding an ionic liquid(IL)can effectively mitigate the dense ionomer ultrathin sublayer formed on the Pt surface,which severely hinders O_(2) transport to the catalyst sites.The molecular dynamics simulation results show that adding the IL significantly alters the ionomer ultrathin sublayer structure by inhibiting its tight arrangement of perfluorosulfonic acid chains but scarcely impacts the ultrathin sublayer thickness.Additionally,the IL addition provides a larger free space for O_(2) dissolution in the ultrathin sublayer.Consequently,due to IL molecules’presence,the O_(2) density in the ultrathin sublayer on the Pt surface is improved by an order of magnitude,which will benefit the catalytic efficiency,and the O_(2) permeation flux across the ionomer film is increased by up to 8 times,which will reduce the O_(2) transport loss of the catalyst layer.
