二氧化锰/石墨烯纸电极的制备及其电化学性能

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

通过电化学法使溶液中的Mn2+电解氧化为Mn O2,沉积复合在石墨烯片膜上,形成由Mn O2/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,Mn O2球形颗粒均匀地沉积在石墨烯片膜上,形成了厚度45μm的纸电极,经过380℃煅烧后,纸电极中的Mn O2晶型由γ-Mn O2转化为β/γ-Mn O2混合晶型,是良好的柔性Li/Mn O2电池的电极材料。Mn O2/石墨烯纸电极在室温下0.1C放电容量达269 m A·h/g,而且电化学阻抗低、柔韧性好。

The flexible MnO2/graphene composite paper electrode for lithium batteries was prepared by electro-deposition of MnO2, via the oxidation of Mn^2＋ 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 MnOE/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/MnOz batteries.