Liu Rui, Jiang Rui, Chu Yu-Han, Yang Wein-Duo
Center of Pharmaceutical Engineering and Technology, School of Pharmacy, Harbin University of Commerce, Harbin 150076, China.
Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan.
Nanomaterials (Basel). 2021 Oct 15;11(10):2736. doi: 10.3390/nano11102736.
A novel MnO/graphene/Ni foam electrode was fabricated via the impregnation and electrochemical deposition technique with Ni foams serving as substrates and graphene serving as a buffer layer for the enhanced conductivity of MnO. The samples were characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Compared with other methods, our strategy avoids using surfactants and high-temperature treatments. The electrodes exhibited excellent electrochemical performance, high capabilities, and a long cycle life. Various electrochemical properties were systematically studied using cyclic voltammetry and electrochemical impedance spectroscopy. The results showed that the specific capacitance of the MnO/graphene/Ni composite prepared at 1 mA cm of electrodeposition could achieve a scan rate of 10 mV s at 292.8 F g, which confirmed that the graphene layer could remarkably improve electron transfer at the electrolyte-electrode interface. The capacitance retention was about 90% after 5000 cycles. Additionally, a MnO/graphene//graphene asymmetric supercapacitor was assembled and it exhibited a high-energy density of 91 Wh kg as well as had an excellent power density of 400 W kg at 1 A g. It is speculated that the strong adhesion between the graphene and MnO can provide a compact structure to enhance the mechanical stability, which can be applied as a new method for energy storage devices.
通过浸渍和电化学沉积技术制备了一种新型的MnO/石墨烯/泡沫镍电极，其中泡沫镍作为基底，石墨烯作为缓冲层以增强MnO的导电性。使用X射线衍射（XRD）、拉曼光谱、扫描电子显微镜（SEM）和X射线光电子能谱（XPS）对样品进行了表征。与其他方法相比，我们的策略避免了使用表面活性剂和高温处理。该电极表现出优异的电化学性能、高容量和长循环寿命。使用循环伏安法和电化学阻抗谱对各种电化学性质进行了系统研究。结果表明，在1 mA cm的电沉积条件下制备的MnO/石墨烯/镍复合材料的比电容在扫描速率为10 mV s时可达292.8 F g，这证实了石墨烯层可显著改善电解质-电极界面处的电子转移。5000次循环后电容保持率约为90%。此外，组装了MnO/石墨烯//石墨烯不对称超级电容器，其在1 A g时表现出91 Wh kg的高能量密度以及400 W kg的优异功率密度。据推测，石墨烯与MnO之间的强附着力可提供紧凑的结构以增强机械稳定性，这可作为储能装置的一种新方法。
