Dielectric-electrolyte supercapacitors
Shian Dong, Weihang Gao, Kunming Shi, Qi Kang, Zhenli Xu, Jinkai Yuan, Yingke Zhu, Hongfei Li, Jie Chen, Pingkai Jiang, Guangning Wu, Qiulong Wei, Jieshan Qiu, Xiaoshi Qian, Xingyi Huang
Abstract
Aqueous supercapacitors (SCs) are highly desirable as the next generation of energy storage devices, holding the promise of being environmentally friendly and free of safety concerns. However, their low water-splitting voltage prevents practical applications. Here, we utilize a dielectric-polymer-coated, hierarchically structured carbon electrode to prepare a dielectric-electrolyte SC (DESC), which exhibits an ultra-high and stable operating voltage of 3 V. The facile design of the polymeric superstructure, covalently bonded upon the porous carbon electrode, allows electrolyte ions to enter and interact with the electrode but effectively blocks water molecules from the entrance. In addition, the dielectric layer could store electrical energy through polarization and provide additional active sites for ion adsorption. Subsequently, the energy density of the DESC is enhanced by over 1,000% compared with the traditionally structured SC. This work may pave a new way for producing low-cost and eco-friendly aqueous SCs with enhanced energy density.