Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Laboratory of Advanced Materials, Fudan University, Shanghai, 200438, P. R. China.
Adv Mater. 2019 Feb;31(5):e1806197. doi: 10.1002/adma.201806197. Epub 2018 Dec 9.
Hybrid supercapacitors generally show high power and long life spans but inferior energy densities, which are mainly caused by carbon negative electrodes with low specific capacitances. To improve the energy densities, the traditional methods include optimizing pore structures and modifying pseudocapacitive groups on the carbon materials. Here, another promising way is suggested, which has no adverse effects to the carbon materials, that is, constructing electron-rich regions on the electrode surfaces for absorbing cations as much as possible. For this aim, a series of hierarchical porous carbon materials are produced by calcinating carbon dots-hydrogel composites, which have controllable surface states including electron-rich regions. The optimal sample is employed as the negative electrode to fabricate hybrid supercapacitors, which show remarkable specific energy densities (up to 62.8-90.1 Wh kg ) in different systems.
混合超级电容器通常具有高功率和长寿命，但能量密度较低，这主要是由于碳负极的比电容较低所致。为了提高能量密度，传统的方法包括优化碳材料的孔结构和修饰赝电容基团。在这里，提出了另一种有前途的方法，即对碳材料没有不利影响的方法，即在电极表面构建富电子区域，以尽可能多地吸收阳离子。为此，通过煅烧碳点-水凝胶复合材料制备了一系列具有可控表面状态（包括富电子区域）的分级多孔碳材料。最佳样品被用作负极来制备混合超级电容器，在不同的体系中表现出显著的比能量密度（高达 62.8-90.1 Wh kg ）。
