The effect of the hot-charging treatment on the performance of AB(2) and AB(5) hydrogen storage alloy electrodes was investigated. The result showed that the treatment can markedly improve the voltage plateau ratio (V...The effect of the hot-charging treatment on the performance of AB(2) and AB(5) hydrogen storage alloy electrodes was investigated. The result showed that the treatment can markedly improve the voltage plateau ratio (VPR), the high rate discharge ability (HRDA), the diffusion coefficient of hydrogen DH and the discharge capacity of the AB2 hydrogen storage alloy electrode. The SEM analysis showed that the hot-charging treatment brings about a Ni-rich surface due to the dissolution of Zr oxides. It is also very helpful for the improvement of the kinetic properties of AB2 hydrogen storage alloy electrode because the microcracking of the surface results in fresh surface. This can be the basic modification treatment for NiMH battery used in electric vehicles (EVs) in the future. But for AB(5) type alloys, the treatment has the disadvantage of impairing the comprehensive electrochemical properties, because the surface of the alloy may be corroded during the treatment. The mechanism of the surface modification of the electrode is also proposed.展开更多
In order to improve the electrochemical kinetic performances of La-Mg-Ni-based alloy,complex surface modification of Ni with excellent catalytic activity and conducting polymer polypyrrole(PPy)was performed via electr...In order to improve the electrochemical kinetic performances of La-Mg-Ni-based alloy,complex surface modification of Ni with excellent catalytic activity and conducting polymer polypyrrole(PPy)was performed via electroless plating method.FESEM images revealed that the complex Ni-PPy treatment resulted in more micropores at the alloy surface,with Ni particles and cotton fiber-shape PPy microspheres attached.Both the larger surface area induced by the micropore and the higher catalytic activity and conductivity on account of the dispersed Ni particles/PPy microspheres promoted the electrode reaction,thereby increasing the discharge capacity of the modified alloy electrode.Electrochemical impedance spectroscopy(EIS)and linear polarization results showed that the Ni-PPy treatment decreased the charge-transfer resistance and increased the exchange current density greatly,far more than the single-component Ni or PPy treatment.Consequently,a notable improvement in high rate dischargeability(HRD)was observed,and at a high discharge current density of 1800 mA/g,the HRD of the modified electrode increased by 10.4%compared with that of the bare electrode.展开更多
文摘The effect of the hot-charging treatment on the performance of AB(2) and AB(5) hydrogen storage alloy electrodes was investigated. The result showed that the treatment can markedly improve the voltage plateau ratio (VPR), the high rate discharge ability (HRDA), the diffusion coefficient of hydrogen DH and the discharge capacity of the AB2 hydrogen storage alloy electrode. The SEM analysis showed that the hot-charging treatment brings about a Ni-rich surface due to the dissolution of Zr oxides. It is also very helpful for the improvement of the kinetic properties of AB2 hydrogen storage alloy electrode because the microcracking of the surface results in fresh surface. This can be the basic modification treatment for NiMH battery used in electric vehicles (EVs) in the future. But for AB(5) type alloys, the treatment has the disadvantage of impairing the comprehensive electrochemical properties, because the surface of the alloy may be corroded during the treatment. The mechanism of the surface modification of the electrode is also proposed.
基金Supported by the National Natural Science Foundation of China(Nos.51571173,51701175,51771164).
文摘In order to improve the electrochemical kinetic performances of La-Mg-Ni-based alloy,complex surface modification of Ni with excellent catalytic activity and conducting polymer polypyrrole(PPy)was performed via electroless plating method.FESEM images revealed that the complex Ni-PPy treatment resulted in more micropores at the alloy surface,with Ni particles and cotton fiber-shape PPy microspheres attached.Both the larger surface area induced by the micropore and the higher catalytic activity and conductivity on account of the dispersed Ni particles/PPy microspheres promoted the electrode reaction,thereby increasing the discharge capacity of the modified alloy electrode.Electrochemical impedance spectroscopy(EIS)and linear polarization results showed that the Ni-PPy treatment decreased the charge-transfer resistance and increased the exchange current density greatly,far more than the single-component Ni or PPy treatment.Consequently,a notable improvement in high rate dischargeability(HRD)was observed,and at a high discharge current density of 1800 mA/g,the HRD of the modified electrode increased by 10.4%compared with that of the bare electrode.
