表层涂碳MlNi3.93Co0.46Mn0.27Al0.34/Co3O4CeO2复合贮氢合金电极制备及电化学性能

Preparation and Electrochemical Performance of Carbon Coated MlNi3.93Co0.46Mn0.27Al0.34/Co3O4CeO2 Composite Hydrogen Storage Alloy Electrode

通过分层涂浆制备表层涂碳的MlNi（3.93）Co（0.46）Mn（0.27）Al（0.34）/Co3O4CeO2电极,并建立表层涂碳的MlNi（3.93）Co（0.46）Mn（0.27）Al（0.34）/Co3O4CeO2电极反应机理模型。物理表征结果表明,活性碳（AC）具有高比表面积,为二维结构,贮氢合金呈块状固体,为单相的CaCu5型六方结构;电化学测试结果表明,活性碳形成双电层的同时也作为导电剂在MlNi（3.93）Co（0.46）Mn（0.27）Al（0.34）/Co3O4CeO2电极表面形成导电网络,可改善贮氢合金电极的电化学性能,在0.2C充放电下,放电比容量292.6mAh·g-1,以1500mAh·g-1倍率放电时,高倍率放电性能（HRD值）为82.5%,循环100次后容量保持率95.91%,在50%DOD下,氢扩散系数及交换电流密度依次为4.7×10-11cm2·s-1,315.6mA·g-1,相比于未涂炭的MlNi（3.93）Co（0.46）Mn（0.27）Al（0.34）/Co3O4CeO2电极,分别提高了2.4mAh·g-1、20.94%、5.53%、38.2%、34.5%。

Carbon coated MlNi（3.93）Co（0.46）Mn（0.27）Al（0.34）/Co3O4CeO2 electrode was prepared by layered coating method and the reaction mechanism model of MlNi（3.93）Co（0.46）Mn（0.27）Al（0.34）/Co3O4CeO2-electrode was established. Physical characterization results show that the active carbon（ AC） has a two-dimensional structure with high specific surface area,and the MlNi（3.93）Co（0.46）Mn（0.27）Al（0.34）/Co3O4CeO2-alloy is block solid with structure of single-phase Ca Cu5 six-party. Electrochemical testing results indicate that the conductive agent AC can form a double electrical layer structure and acts as conductive agent to form a conductive network on the surface of MlNi（3.93）Co（0.46）Mn（0.27）Al（0.34）/Co3O4CeO2 electrode,which effectively improves the electrochemical performance of hydrogen storage alloys. Compared to the MlNi（3.93）Co（0.46）Mn（0.27）Al（0.34）/Co3O4CeO2-electrode with no carbon coating,the discharge specific capacity of carbon coated MlNi（3.93）Co（0.46）Mn（0.27）Al（0.34）/Co3O4CeO2-electrode was 292. 6 m Ah·g-1 and retention capacity was 95. 91% after 100 cycles at 0. 2 C,and HRD value was 82. 5% under the current density of 1500 m Ah·g-1,the hydrogen diffusion coefficient was 4. 7×10-11 cm2·s-1 and the exchange current density was 315. 6 m A·g-1 under 50% DOD,which were increased by 2. 4 m Ah·g-1,20. 94%,5. 53%,38. 2% and 34. 5%,respectively.