超级电容器是一种具有高功率密度、优秀循环性能、高安全性的高性能储能装置,然而其低能量密度限制其发展,为进一步提升超级电容器的能量密度,满足日益增长的储能需求,提升电极材料的电化学性能是关键。为提高粉煤灰基硅酸锰/氧化锰的电化学性能,采用静电组装法合成了氧化石墨烯与粉煤灰基硅酸锰/氧化锰的复合材料(FA@MS/MO/GO),通过调节氧化石墨烯加入量优化其电化学性能,并研究了氧化石墨烯对于粉煤灰基硅酸锰/氧化锰电化学性能的影响机制,通过XRD、SEM、XPS、FTIR表征材料的形貌与结构,并采用循环伏安法、恒电流充放电、交流阻抗测试对材料和器件性能进行测试。结果表明,优化后的FA@MS/MO/GO-2的电荷传输速率大幅提升,FA@MS/MO/GO-2在0.5A/g电流密度下的比电容为737.4F/g,高于未与氧化石墨烯复合的FA@MS/MO(293.4F/g),电流密度由0.5A/g升高至8.0A/g,FA@MS/MO/GO-2容量保持率最好(67%),高于FA@MS/MO(44%)。FA@MS/MO/GO-2与商业活性炭分别为正负极组装为非对称超级电容器后,该器件能量密度达15.75Wh/kg(功率密度375W/kg),在5A/g下循环10000次的容量保持率和库伦效率均可达100%,表明该电极材料拥有长期循环利用潜力,具有良好应用前景。

Supercapacitors are highperformance energy storage devices with high power density, excellent cycling performance and highsafety. However, their low energy density limits their development. In order to further improve the energy density of supercapacitorsand meet the growing demand for energy storage, improving the electrochemical performance of electrode materials is the key. In order toimprove the electrochemical performance of fly ashbased manganese silicate/ manganese oxide, graphene oxide and fly ashbased manganese silicate/ manganese oxide composites were synthesized by electrostatic assembly method, and their electrochemical performance wasoptimized by adjusting the amount of graphene oxide added. The mechanism of the effect of graphene oxide on the electrochemical performance of fly ashbased manganese silicate/ manganese oxide was also studied. The morphology and structure of the materials were characterized by XRD, SEM, XPS and FTIR, and the properties of the materials and devices were tested by Cyclic Voltammetry, GalvanostaticChargeDischarge and Electrochemical Impedance Spectroscopy. The results show that the charge transfer rate of FA@ MS/ MO/ GO- 2is greatly improved after optimization, and FA@ MS/ MO/ GO-2 has a specific capacitance of 737.4 F/ g at a current density of 0.5 A/ g,which is higher than that of FA@ MS/ MO not compounded with graphene oxide(293.4 F/ g). FA@ MS/ MO/ GO-2 has the best capacityretention rate (67%) when the current density increases from 0.5 A/ g to 8.0 A/ g, which is higher than that of FA@ MS/ MO(44%). After FA@ MS/ MO/ GO-2 and commercial activated carbon are respectively assembled as positive and negative electrodes for asymmetric supercapacitors, the energy density of the device can reach 15.75 Wh/ kg (power density is 375 W/ kg), and the capacity retention rateand coulombic efficiency can reach 100% at 10 000 cycles at 5 A/ g, which shows that the electrode material has the potential of longtermrecycling and has a good practical application prospect.

0 引言

1 试验

   1.1 原料与试剂

   1.2 氧化石墨烯/粉煤灰基硅酸锰/氧化锰复合材料的制备

   1.3 FA@MS/MO/GO复合材料的表征

   1.4 电极制备及电化学性能测试

2 结果与讨论

   2.1 微观形貌与结构分析

   2.2 电化学性能比较

3 结论