石墨烯/δ-MnO2复合材料的制备及其超级电容器性能

采用螯合法制备了RGO/δ-MnO₂复合材料，并用X射线粉末衍射（XRD）、低压氮气吸附脱附（BET）、X射线光电子能谱（XPS）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、能谱（EDS）、热重（TGA）对其结构和物相进行表征。采用循环伏安测试（CV）、恒电流充放电（GCD）以及循环测试对所制材料电化学储能进行测试。结果表明RGO/δ-MnO₂复合材料比纯石墨烯和纯δ-MnO₂具有更优异的电化学性能。当电流密度为1 A·g^-1时，RGO/δ-MnO₂复合材料的比电容可达322.6 F·g^-1，比纯δ-MnO₂电极材料高234.2 F·g^-1，比纯石墨烯高212.1 F·g^-1。当电流密度放大10倍后，RGO/δ-MnO₂复合材料的比电容保留率为79.1%。在1000次恒流充放电测试后，比电容为252 F·g^-1（99.6%），说明该方法制备的RGO/δ-MnO₂复合材料是一种有应用前景的超级电容器电极材料。

Preparation of graphene/δ-MnO2 composites and supercapacitor performance

This work mainly uses the one pot to synthesis RGO/δ-MnO₂ composites, which is characterized using X-ray powder diffraction (XRD), low pressure nitrogen adsorption stripping (BET), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM), energy spectrum (EDS) and thermal gravimetric analyzer (TGA). The electrochemical performance is tested by the cyclic voltammetry (CV), constant current charge/discharge test (GCD) and loop test. Results show that the RGO/δ-MnO₂ composites possess more excellent electrochemical performance than pure δ-MnO₂ and pure graphene. When the current density is 1 A·g^-1, the specific capacitance of RGO/δ-MnO₂ composite can reach 322.6 F·g^-1, which is higher than that of the pure δ-MnO₂ (234.2 F·g^-1) and the pure graphene (212.1 F·g^-1). Moreover, the specific capacitance retention of RGO/δ-MnO₂ composites remains 79.1% when current density increases to 10 A·g^-1. The specific capacitance of RGO/δ-MnO₂ composite is still as high as 252 F·g^-1 (99.6%) even after 1000 times constant current charge/discharge tests. These results indicate that the composite will be a kind of promising supercapacitor electrode material.