二氧化锰/石墨烯纸电极的制备及其电化学性能

通过电化学法使溶液中的Mn²⁺电解氧化为MnO₂,沉积复合在石墨烯片膜上,形成由MnO₂/石墨烯复合材料构成的纸电极。 采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)、循环伏安(CV)和恒流放电等技术手段对纸电极材料的结构、形貌以及电化学性能进行了研究。 结果表明,MnO₂球形颗粒均匀地沉积在石墨烯片膜上,形成了厚度45 μm的纸电极,经过380 ℃煅烧后,纸电极中的MnO₂晶型由γ-MnO₂转化为β/γ-MnO₂混合晶型,是良好的柔性Li/MnO₂电池的电极材料。 MnO₂/石墨烯纸电极在室温下0.1C放电容量达269 mA·h/g,而且电化学阻抗低、柔韧性好。

Preparation and Electrochemical Characteristics of Manganese Dioxide/graphene Composite Paper Electrode

The flexible MnO₂/graphene composite paper electrode for lithium batteries was prepared by electro-deposition of MnO₂, via the oxidation of Mn²⁺ solution, on the graphene film. The paper electrode structure, appearance and electrochemical performances were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), cyclic voltammetry (CV) and galvanostatic discharging. The results show that spherical MnO₂ particles are homogeneously deposited on the graphene flakes to form a MnO₂/graphene composite paper electrode with the thickness of 45 μm. The crystal structure of MnO₂ in the composite changes from γ-MnO₂ to a mixed structure of γ/β-MnO₂ after calcination at 380 ℃. The discharge capacity of MnO₂ in the composite can reach 269 mA·h/g at 0.1C at room temperature. The structure of graphene is not damaged at the high calcination temperature. The good flexibility, low impendence and excellent electrochemical performance of the MnO₂/graphene paper electrode are profitable for flexible Li/MnO₂ batteries.