层状MnO2纳米带的插层质子化及其与氧化石墨烯复合材料的电化学性能

Protonation of layered MnO2 nanobelts and GO/MnO2 composites and their electrochemical properties

利用KMnO4和MnCl2在高浓度KOH溶液中发生氧化还原反应,再经200℃保温48 h后合成K^+插层的α-MnO2纳米材料,之后利用过硫酸铵进行质子化,并以氧化石墨烯水溶液作为溶剂制备氧化石墨烯(GO)复合物/层状MnO2(GO/MnO2)。采用X射线衍射仪、扫描电子显微镜等对制备的材料进行物相和形貌表征,并将其作为超级电容器的电极材料在1M KOH溶液中进行循环伏安(CV)、恒电流充放电(GCD)等电化学性能测试。结果表明:K^+插层的MnO2具有纳米带形貌,长度可达5~12μm,宽约500 nm。质子化后仍可保持较高的结晶度和带状形貌。此外,通过复合GO,可显著提高MnO2的电化学性能,层状MnO2纳米带/GO复合物在0.5 A/g的电流密度下比电容高达750 F/g。

K^+ intercalated-MnO2 nanomaterials were synthesized by using KMnO4 and MnCl2 as redox in KOH solution,placed at 200℃ for 48h,then protonated with ammonium persulfate.In addition,layered MnO2/graphene oxide(GO)composites were prepared by using graphene oxide aqueous solution as solvent.The phase and morphology of the prepared materials were characterized by XRD,SEM,etc.The electrochemical performance of the supercapacitor was tested by cyclic voltammetry(CV)and galvanostatic charge-discharge(GCD)in 1 M KOH solution.The results show that the K^+ intercalated MnO2 has the morphology of nanobelts,its length can reach 5−12μm,and its width is about 500 nm.After protonation,high crystallinity and nanobelt morphology can be maintained.In addition,the electrochemical properties of MnO2 can be significantly improved by the addition of GO.The specific capacitance of layered MnO2 nanobelts/GO composites is as high as 750 F/g at current density of 0.5 A/g.