介孔-C/MnO_2 非对称超级电容器的研究

Study on Meso-C/MnO_2 Asymmetric Supercapacitors

以氧化硅介孔分子筛SBA-15为模板制备出介孔MnO2和介孔炭,并分别作为正极和负极在6mol·L-1KOH电解液中组装出新型非对称超级电容器.小角X射线衍射(LXRD)、透射电镜(TEM)以及N2吸附-脱附测试表明样品具有介孔结构,且比表面积较大,孔径分布范围较窄.采用恒流充放电、循环伏安、交流阻抗等电化学方法考察了非对称超级电容器的性能.在0.1A·g-1电流密度、不同充放电电位下进行研究,得出最佳充放电电位为1.8V.结果表明,在0.1A·g-1电流密度、1.8V的充放电电位下电容器的充放电性能良好,等效串联电阻(ESR)为1.15Ω,功率密度为89.0W·kg-1,能量密度达31.3Wh·kg-1,首次放电比容量为76.7F·g-1,经过1000次循环容量仍保持在69.5F·g-1.

Mesoporous MnO2 and mesoporous carbon were prepared using silica mesoporous molecular sieves （SBA-15） as a hard template. A meso-C/MnO2 asymmetrical supercapacitor was assembled and characterized in 6 mol· L^-1 KOH electrolyte. Low X-ray diffraction （LXRD）, transmission electron microscopy （TEM）, and nitrogen adsorptiondesorption results indicated that the as-prepared samples had mesoporous structures, large specific surface areas, and a narrow pore diameter distribution range. Galvanostatic charge/discharge, cyclic voltammetry, and AC （altemating current） impedance were used to investigate the electrochemical performance. At 0.1 A ·g^-1 current density, different potentials were applied to obtain the optimum cell voltage of 1.8 V. Under this condition, the supercapacitor exhibited good charge/discharge capacities. Results showed that the equivalent series resistance （ESR）, power density, and energy density were 1.15 Ω, 89.0 W·kg^-1, and 31.3 Wh ·kg^-1, respectively. The initial specific capacitance was 76.7 F·g^-1 and 69.5 F· g^-1 was obtained after 1000 cycles.