High performance cathode for polymer electrolyte membrane fuel cell was prepared by depositing Pt nanowires in a carbon matrix coated on a substrate, and using decal transfer method to fabricate the membrane electrode...High performance cathode for polymer electrolyte membrane fuel cell was prepared by depositing Pt nanowires in a carbon matrix coated on a substrate, and using decal transfer method to fabricate the membrane electrode assembly. The effects of carbon and ionomer contents on the electrode micro-structure and fuel cell performance are investigated by physical characterization and single cell testing. The Pt nanowires are gradient distributed across the cathode thickness, and more Pt exists near the membrane. Both the carbon and ionomer contents can affect the Pt nanowires distribution and aggregation. In addition, the carbon loading dominates the transport distance of gas and proton, and the ionomer content affects the triple phase boundaries and porosity in the cathode. The optimal structure of Pt nanowire cathode is obtained at 0.10 mg·cm^-2 carbon loading and 10 wt% ionomer.展开更多
Supercapacitors based on electric double layers are prone to serious self-discharge due to electrolyte ion desorption and the resulting energy loss severely limits the application range of supercapacitors.Rational des...Supercapacitors based on electric double layers are prone to serious self-discharge due to electrolyte ion desorption and the resulting energy loss severely limits the application range of supercapacitors.Rational design of polymer electrolyte systems to address this problem shows considerable generality and high feasibility.Herein,we reported a quasi-solid-state bipolar ionomer electrolyte prepared by an in-situ layer-by-layer ultraviolet-curing method,which has an integrated Janus structure with an intermediate binding layer.Based on the synergistic effect of confining impurity ions by ionizable groups and electrostatic repulsion to stabilize the electric double layers and superimposing synergies on both sides,the assembled device not only possesses ideal supercapacitor characteristics,but also exhibits an ultrahigh voltage retention of 71% after being left to stand for 100 h after being fully charged.Furthermore,through the quasi-in-situ energy dispersive X-ray spectroscopy linear scanning,the characteristics of ion diffusion in this ionomer electrolyte are revealed,suggesting its correlation with self-discharge behavior.展开更多
The design of the catalyst layer(CL)offers a feasible way to realize the commercialization of proton exchange membrane fuel cells(PEMFCs).An in-depth understanding of catalyst inks is critical to achieving the optimal...The design of the catalyst layer(CL)offers a feasible way to realize the commercialization of proton exchange membrane fuel cells(PEMFCs).An in-depth understanding of catalyst inks is critical to achieving the optimal CL structure and cell performance.In this work,the effects of the solvent evaporation process during ink drying on the formation of the CL microstructure are particularly considered to reveal the structure-property correlations among the catalyst ink,drying process,CL microstructure and fuel cell performance.An increase in the alcohol content of the catalyst ink increases the amount of free ionomers while allowing the ionomer backbone to be more stretched in the dispersion medium.The higher alcohol content contributes to rapid solvent evaporation and thus inhibits the formation of coffee rings;as a result,a more developed ionomer network with a denser pore structure is obtained.Therefore,the alcohol-rich electrode exhibits better proton conduction capability,but higher oxygen transport resistance.For complex fuel cell operating conditions,a catalyst ink formulation with 50 wt%alcohol content is preferred due to its proper ionomer and pore size distribution,providing satisfactory fuel cell performance.展开更多
文摘High performance cathode for polymer electrolyte membrane fuel cell was prepared by depositing Pt nanowires in a carbon matrix coated on a substrate, and using decal transfer method to fabricate the membrane electrode assembly. The effects of carbon and ionomer contents on the electrode micro-structure and fuel cell performance are investigated by physical characterization and single cell testing. The Pt nanowires are gradient distributed across the cathode thickness, and more Pt exists near the membrane. Both the carbon and ionomer contents can affect the Pt nanowires distribution and aggregation. In addition, the carbon loading dominates the transport distance of gas and proton, and the ionomer content affects the triple phase boundaries and porosity in the cathode. The optimal structure of Pt nanowire cathode is obtained at 0.10 mg·cm^-2 carbon loading and 10 wt% ionomer.
基金financial supports of National Natural Science Foundation of China(21875065,51673064,22109045)the China Postdoctoral Science Foundation Special Fund(2022T150211)the China Postdoctoral Science Foundation(2021M701191)。
文摘Supercapacitors based on electric double layers are prone to serious self-discharge due to electrolyte ion desorption and the resulting energy loss severely limits the application range of supercapacitors.Rational design of polymer electrolyte systems to address this problem shows considerable generality and high feasibility.Herein,we reported a quasi-solid-state bipolar ionomer electrolyte prepared by an in-situ layer-by-layer ultraviolet-curing method,which has an integrated Janus structure with an intermediate binding layer.Based on the synergistic effect of confining impurity ions by ionizable groups and electrostatic repulsion to stabilize the electric double layers and superimposing synergies on both sides,the assembled device not only possesses ideal supercapacitor characteristics,but also exhibits an ultrahigh voltage retention of 71% after being left to stand for 100 h after being fully charged.Furthermore,through the quasi-in-situ energy dispersive X-ray spectroscopy linear scanning,the characteristics of ion diffusion in this ionomer electrolyte are revealed,suggesting its correlation with self-discharge behavior.
基金financially supported by the National Key Research and Development Program of China(2018YFB1502503)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA21090101)。
文摘The design of the catalyst layer(CL)offers a feasible way to realize the commercialization of proton exchange membrane fuel cells(PEMFCs).An in-depth understanding of catalyst inks is critical to achieving the optimal CL structure and cell performance.In this work,the effects of the solvent evaporation process during ink drying on the formation of the CL microstructure are particularly considered to reveal the structure-property correlations among the catalyst ink,drying process,CL microstructure and fuel cell performance.An increase in the alcohol content of the catalyst ink increases the amount of free ionomers while allowing the ionomer backbone to be more stretched in the dispersion medium.The higher alcohol content contributes to rapid solvent evaporation and thus inhibits the formation of coffee rings;as a result,a more developed ionomer network with a denser pore structure is obtained.Therefore,the alcohol-rich electrode exhibits better proton conduction capability,but higher oxygen transport resistance.For complex fuel cell operating conditions,a catalyst ink formulation with 50 wt%alcohol content is preferred due to its proper ionomer and pore size distribution,providing satisfactory fuel cell performance.
