纳米多孔铜银/二氧化锰复合电极材料的制备及储能研究

Fabrication and Electrochemical Properties of Nanoporous CuAg Bimetal/Manganese Dioxide Composite Electrodes

以Cu-Zr-Ag非晶合金作为前驱体,利用快速凝固技术和脱合金相结合的方法制备纳米多孔铜银双金属(NP-CuAg),通过化学沉淀法使MnO_2在NP-CuAg上形核生长,制备出NP-CuAg和MnO_2的复合电极材料(NP-CuAg/MnO_2)。利用XRD、SEM分析材料的相组成及微观形貌,通过循环伏安法和恒流充放电法研究复合电极材料的电容特性。结果表明:兼具三维连续纳米孔洞结构及优异导电性的NP-CuAg作为依附载体可大幅度提高MnO_2颗粒的分散度和电极材料导电性,使其电化学性能得以充分发挥。复合电极材料的比电容值随着前驱体合金中银含量的增加而提高,前驱体合金中Ag含量为10 at%时电容值可达392.86 F/g。封装成可反复充放电的纽扣型电化学储能器件,可成功对LED灯泡供电。

The NP-CuAg were prepared by chemical dealloying and rapid solidification using the Cu-Zr-Ag metallic glasses as precursor. The nanoporous CuAg bimetal/manganese dioxide(NP-CuAg/MnO2) composites as electrode materials were synthesized by chemically depositing manganese dioxide(MnO2) on nanoporous CuAg bimetal(NP-CuAg). The phase composition and microstructure of NP-CuAg and NP-CuAg/MnO2 composite materials were examined by XRD and SEM. The electrochemical properties of the NP-CuAg/MnO2 composite electrode materials were investigated by cyclic voltammetry and galvanostat ic charge-discharge measurements. Results show that for the NP-CuAg-supported MnO2 composites, the MnO2 nanoflakes are deposited on the surface of the NP-CuAg substrate. Owing to the three dimensional continuous nanoporous structure and excellent electrical conductivity of NP-CuAg, the MnO2 nanoflakes can produce much larger surface area as compared to its aggregate particles. Moreover, the NP-CuAg/MnO2 composite materials exhibit higher electrical conductivity than the NPC/MnO2 composite materials. Thus, the utilization of MnO2 surface active sites is improved, which leads to the higher specific capacitance. The specific capacitance increases with the increase of the Ag content in the precursor alloy. Cu45Zr45Ag10 ribbon after dealloying in 0.1 mol/L HF for 10 h, the specific capacitance reaches 392.86 F/g. The button type energy storage device encapsulated by the NP-CuAg/MnO2 composite electrode materials, is able to light on the LED.