基于石墨和二氧化锰纳米花复合电极的超级电容器研究

Graphite/MnO_2 Hybrid Nanoflowers Electrodes-Based High-Performance Supercapacitors

二氧化锰(MnO_2)虽然具有较高比电容(Cs),但是低导电率和循环稳定性差制约了它在超级电容器上的广泛应用。采用水浴、磁搅拌同步的方法制备二氧化锰纳米花(MnO_2NFs)新材料,将合成后的MnO_2NFs和导电石墨(G)按一定比例混合均匀后自然沉积在碳纸上,构建G/MnO_2NFs新型复合电极。实验结果表明,该电极有效降低了电荷传递电阻,提高了电导率,促进了离子和电子在电极和电解液中的传输,能够获得优异电化学性能。在循环扫描速度为5 m V/s时,复合电极的比电容(Cs)达506 F/g,同时具有较高循环稳定性。此外,实验还成功构建了以G/MnO_2NFs为电极的对称超级电容器(SSCs),其最大能量密度为86.4 WH/kg,功率密度为8.2 kW/kg。简易、高效的G/MnO_2NFs复合材料有望成为高性能超级电容器的主要电极材料。

Although MnO2 has a high specific capacitance,low conductivity and poor cyclic stability are still the main obstacles to its wide application in supercapacitors.Developing a facile and inexpensive approach of boiling water-bath with simultaneous magnetically stirring to synthesize MnO2 nanomaterials.In this paper,we report a novel structure of conducting graphite(G)/MnO2 nanoflowers(NFs)hybrid electrodes,where conducting graphite and MnO2 nanomaterials hybrid solution were natural deposition onto carbon paper.Such nanoflowers structures effectively decrease the charge transport resistance and facilitate ion and electron transmission in the electrode.The G/MnO2 NFs hybrid electrodes exhibit a high specific capacitance(Cs)of 506 F/g at the scan rate of 5 mV/s,high energy/power densities,and excellent cycling stability with 94%capacitance retained over 2 000 cycles.Furthermore,symmetrical supercapacitors(SSCs)with G/MnO2 NFs hybrid materials as electrodes were successfully fabricated,which achieved promising characteristics with a maximum an energy density of 86.4 Wh/kg,power density of 8.2 kW/kg.Such low-cost,high-performance carbon paper-based G/MnO2 NFs hybrid electrodes may hold promise for superior performance supercapacitors.