纳米多孔铜银/二氧化锰复合电极材料的制备及储能研究

The Preparation of Nanoporous CuAg Bimetal/Manganese Dioxide Composites and High Performance Button Type Electrochemistry Energy Storage Device

摘要:

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MnO₂在NP-CuAg上形核生长,成功制备出NP-CuAg和MnO₂的复合电极材料(NP-CuAg/MnO₂)。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MnO₂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。

Abstract:

Nanoporous CuAg bimetal/manganese dioxide (NP-CuAg/MnO₂) composites as electrode materials have been successfully synthesized by chemically depositing manganese dioxide (MnO₂) on nanoporous CuAg bimetal (NP-CuAg). NP-CuAg can be produced by chemical dealloying the Cu-Zr-Ag metallic glasses. The phases and microstructures 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 galvanostatic charge-discharge measurements. 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 M HF for 10 h, the specific capacitance reaches to 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.