Facile synthesis of ternary MnO2/graphene nanosheets/carbon nanotubes composites with high rate capability for supercapacitor applications
Facile synthesis of ternary MnO2/graphene nanosheets/carbon nanotubes composites with high rate capability for supercapacitor applications
复制标题
DOI：
10.1016/j.electacta.2015.05.155
复制
发表时间：
2015-08
影响因子：
6.6
通讯作者：
M. Ramezani;M. Fathi;F. Mahboubi
中科院分区：
文献类型：
--
作者：
M. Ramezani;M. Fathi;F. Mahboubi
通过在氧化石墨烯(GO)/碳纳米管(CNT)杂化材料表面原位生长MnO2颗粒，然后通过GO的化学还原，制备了MnO2/石墨烯纳米片/碳纳米管(MnO2/GNS/CNTs)三元复合材料。用扫描电子显微镜(SEM)、能谱仪(EDS)、紫外可见光谱(UV/Vis)和X射线衍射仪(X射线衍射仪)对材料的形貌和结构进行了表征。通过循环伏安(CV)、恒流充放电和交流阻抗谱(EIS)技术研究了样品电极在1M Na2SO4水溶液中的超电容行为。电化学测试表明，在扫描速度为20F/S−1(367F/g−1)时，复合材料的比电容远高于纯MnO_2(55.7F/g−1)、二元MnO_2/碳纳米管(180F/g−1)和MnO_2/GNS(310F/g−1)复合材料。此外，MnO2/GNS/CNT复合材料表现出优异的倍率性能，在5倍的电位扫描速度下保持了79.3%的容量保持率，并具有更好的循环稳定性，3000次循环后的容量保持率为83%。这些进展可以归因于GNS和CNT在复合结构中的协同作用，它促进了电极材料在电化学过程中接触到电解质离子，并保持了机械强度。
Ternary composites of manganese dioxide/graphene nanosheets/carbon nanotubes (MnO2/GNS/CNTs) have been fabricated through a facile chemical method involving in situ growth of MnO2particles on the surface of graphene oxide (GO)/CNT hybrid following by the chemical reduction of GO. The morphology and structure of the resulting materials are characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), ultraviolet/visible (UV/Vis) spectroscopy and X-ray diffraction (XRD). The supercapacitive behaviors of the sample electrodes are evaluated by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) techniques in 1 M Na2SO4aqueous solution. The electrochemical measurements show that the specific capacitance of MnO2/GNS/CNT composite at the scan rate of 20 mV s−1(367 F g−1) is much higher than that of pure MnO2(55.7 F g−1), binary MnO2/CNT (180 F g−1) and MnO2/GNS (310 F g−1) composites. In addition, the MnO2/GNS/CNT composite shows excellent rate capability, with 79.3% capacitance retention after a 5-fold increase in potential scan rate and better cycling stability, with 83% capacitance retention after 3000 cycles. These advances can be attributed to the synergistic effects of GNS and CNT in the composite structure, which facilitates electrolyte ions accessibility to the electrode material during electrochemical process as well as maintaining the mechanical strength.