非真空热压烧结Pb-Co阳极的电化学性能和微观结构

Electrochemical Properties and Microstructure of Pb-Co Anode Prepared by Hot Pressing Treatment in Non-Vacuum

为制备一种低析氧电位、低腐蚀速率且低成本的Pb基合金阳极,采用非真空热压烧结工艺在温度分别为280,300℃和轴向压力为800 MPa的条件下制备了Pb-1%Co,Pb-2%Co和Pb-3%Co阳极材料,通过Tafel曲线、循环伏安曲线、交流阻抗和扫描电镜(SEM)等分析了这6种阳极材料极化48 h后的电化学性能和微观结构。结果表明:随着Co含量的增大,Pb-Co阳极的析氧电位降低,随烧结温度升高,Pb-Co阳极的析氧电位增大; Co含量相同时烧结温度为280℃制备的Pb-Co阳极比300℃制备的Pb-Co阳极具有较低的析氧过电位和更大的表观交流电流密度,说明烧结温度为280℃时更容易发生阳极反应;当Co含量增大到3%时,Pb-Co阳极极化48 h后表面会发生钝化反应;随着Co含量的增大,阳极极化48 h后的Pb-Co阳极膜晶粒尺寸减小,结构更加致密。

Pb-1%Co,Pb-2%Co and Pb-3%Co anode materials were prepared by hot pressing at 280 ℃ under 800 MPa and at 300 ℃ under800 MPa,respectively. The electrochemical properties and microstructure of the six kinds of anode materials after polarization for 48 h were analyzed by Tafel curves,cyclic voltammetry curves,electrochemical impedance spectroscopy( EIS) and scanning electron microscope( SEM).Results showed that the oxygen evolution reaction( OER) potential decreased with the increase of Co content,and increased with the increase of sintering temperature. When the Co content was the same,Pb-Co anode with sintering temperature of 280 ℃ possessed a lower oxygen evolution over-potential and a higher apparent alternating current density,which indicated that the anode reaction occurred more easily on the anode materials prepared at 280 ℃. When the Co content increased to 3%,the passivation reaction occurred on the anode material surface after polarization for 48 h. With the increase of Co content,the anodic film after polarization for 48 h possessed lower grain size and denser structure.