Robust Negative Electrode Materials Derived from Carbon Dots and Porous Hydrogels for High‐Performance Hybrid Supercapacitors

• Published in: Advanced materials (Weinheim) Vol. 31; no. 5; pp. e1806197 - n/a
• Main Authors: Wei, Ji‐Shi, Ding, Chen, Zhang, Peng, Ding, Hui, Niu, Xiao‐Qing, Ma, Yuan‐Yuan, Li, Chao, Wang, Yong‐Gang, Xiong, Huan‐Ming
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.02.2019
• Subjects: Carbon; Carbon dots; Construction materials; Electrode materials; Electrodes; hierarchical porous carbons; hybrid supercapacitors; Hydrogels; Lithium; Materials science; Optimization; Porous materials; Supercapacitors; surface states; surface states; hybrid supercapacitors; carbon dots; hierarchical porous carbons; hydrogels
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201806197

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−1) in different systems. Robust carbon negative electrodes for hybrid supercapacitors are fabricated by a new promising method, that is, constructing electron‐rich regions on the electrode surfaces for absorbing cations as much as possible. Correspondingly, hierarchical porous carbon materials are produced by calcinating carbon dots–hydrogel composites, which have controllable surface states including electron‐rich regions.