Fabrication of novel electrode materials with ordered proton-migration channels is an effective strategy to enhance the proton conductivity of the electrode for polymer electrolyte membrane fuel cells. Here we report ...Fabrication of novel electrode materials with ordered proton-migration channels is an effective strategy to enhance the proton conductivity of the electrode for polymer electrolyte membrane fuel cells. Here we report the electrochemical fabrication of ordered Nafion？ionomers decorated polypyrrole nanowires to construct the ordered proton-migration channels. Based on the electrostatic interaction between Nafion？ionomers and the polymer intermediate, ordered Nafion？ionomers decorated polypyrrole nanowires could be fabricated via chronoamperometry with varying contents of Nafionionomers. The morphologies, charge-storage performances, electron conductivity and proton conductivity of the composites are investigated by scanning electron microscopy, cyclic-voltammetry, galvanostatic charge–discharge measurement and electrochemical impedance spectroscopy. With the modification effect of Nafionionomers on polypyrrole nanowires, the composite shows greater ordered structure relative to another without Nafion？ionomers and the electrochemical performances change with the content of Nafion？ionomers.The composite could achieve a high specific capacitance of 356 F/g at 1 A/g with a 0.62-fold enhancement compared to polypyrrole nanowires without Nafion？ionomers. It also displays a superior electrical conductivity of 49 S/cm and a quite high proton conductivity of 0.014 S/cm at working conditions of fuel cells, which are associated with the requirements of fuel cells and have the potential to be the electrode material for a large range of electrochemical energy conversion devices.展开更多
As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal...As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.展开更多
基金financially supported by the National Natural Science Foundation of China(No.21503228,No.21506209)
文摘Fabrication of novel electrode materials with ordered proton-migration channels is an effective strategy to enhance the proton conductivity of the electrode for polymer electrolyte membrane fuel cells. Here we report the electrochemical fabrication of ordered Nafion？ionomers decorated polypyrrole nanowires to construct the ordered proton-migration channels. Based on the electrostatic interaction between Nafion？ionomers and the polymer intermediate, ordered Nafion？ionomers decorated polypyrrole nanowires could be fabricated via chronoamperometry with varying contents of Nafionionomers. The morphologies, charge-storage performances, electron conductivity and proton conductivity of the composites are investigated by scanning electron microscopy, cyclic-voltammetry, galvanostatic charge–discharge measurement and electrochemical impedance spectroscopy. With the modification effect of Nafionionomers on polypyrrole nanowires, the composite shows greater ordered structure relative to another without Nafion？ionomers and the electrochemical performances change with the content of Nafion？ionomers.The composite could achieve a high specific capacitance of 356 F/g at 1 A/g with a 0.62-fold enhancement compared to polypyrrole nanowires without Nafion？ionomers. It also displays a superior electrical conductivity of 49 S/cm and a quite high proton conductivity of 0.014 S/cm at working conditions of fuel cells, which are associated with the requirements of fuel cells and have the potential to be the electrode material for a large range of electrochemical energy conversion devices.
基金supported by the Key Research and Development Program of Sichuan Province(Grant No.2023ZHCG0050)the Fundamental Research Funds for the Central Universities of China(Grant No.2682024QZ006 and 2682024ZTPY042)the Analytic and Testing Center of Southwest Jiaotong University.
文摘As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.
