La-Nd-Y-Ni系A_(5)B_(19)型储氢合金表面原位合成Ni_(3)S_(2)@MoS_(2)改性及其电化学性能

In situ synthesis of Ni_(3)S_(2)@MoS_(2)on the surface of La-Nd-Y-Ni based A_(5)B_(19)-type hydrogen storage alloy and its electrochemical properties

储氢合金电极在碱性溶液中充放电时其表面通常会发生严重的腐蚀或氧化,这会显著影响合金电极的循环稳定性和高倍率放电性能,限制了其作为镍氢电池负极材料的应用。以A_(5)B_(19)型La-Nd-Y-Ni系La_(0.25)Nd_(0.2)Y_(0.55)Ni_(6.1)Co_(1.5)Mn_(0.9)Al_(0.9)合金为研究对象,以四硫代钼酸铵((NH)_(2)MoS_(4))为前驱体溶液,采用不同温度下的水热处理方法,实现了在合金表面原位生长Ni_(3)S_(2)@MoS_(2)利用XRD、SEM/EDS、XPS和电化学方法研究了水热处理和Ni_(3)S_(2)@MoS_(2)对合金及其电化学性能的影响规律和作用。结果表明,经表面原位生长Ni_(3)S_(2)@MoS_(2)后可不同程度的改善和提高合金电极的循环寿命和高倍率性能,其中经120℃处理后的合金电极循环寿命最佳(S_(100)=92%),而160℃处理后的合金电极的高倍率性能(HRD_(1800)=65.8%)明显优于未处理合金(HRD1800=37.3%)。

Hydrogen storage alloy electrodes usually undergo severe corrosion or oxidation on their surfaces when charged and discharged in alkaline solutions,which significantly affects the cycling stability and high rate discharge performance of the alloy electrodes and limits their application as anode materials for Ni-MH batteries.La_(0.25)Nd_(0.2)Y_(0.55)Ni_(6.1)Co_(1.5)Mn_(0.9)Al_(0.9)alloy of La-Nd-Y-Ni system of A_(5)B_(19)type was studied,and the precursor solution of ammonium tetrathiomolybdate((NH_(4))_(2)MoS_(4))was used as the precursor,and the hydrothermal treatment at different temperatures was used to achieve the in situ growth of Ni_(3)S_(2)@MoS_(2)was grown in situ on the surface of the alloy using hydrothermal treatment at different temperatures.The effects of hydrothermal treatment and Ni_(3)S_(2)@MoS_(2)on the alloy and its electrochemical properties were investigated by XRD,SEM/EDS,XPS and electrochemical methods.The results showed that the cycle life and high-magnification performance of the alloy electrode could be improved and enhanced to different degrees after in situ growth of Ni_(3)S_(2)@MoS_(2)on the surface,among which the cycle life of the alloy electrode treated at 120 C was the best(S_(100)=92%),while the high-magnification performance of the alloy electrode treated at 160℃(HRDisoo=65.8%)was significantly better than that of the untreated alloy(HRD_(1800)=37.3%).