Achieving commercial-level mass loading in ternary-doped holey graphene hydrogel electrodes for ultrahigh energy density supercapacitors

Research paper by Zhenghui Pan, Huozhen Zhi; Yongcai Qiu; Jie Yang; Lidan Xing; Qichong Zhang; Xiaoyu Ding; Xianshu Wang; Guoguang Xu; Hua Yuan; Min Chen; Wanfei Li; Yagang Yao; Nunzio Motta; Meinan Liu; Yuegang Zhang

Indexed on: 01 Mar '18Published on: 26 Feb '18Published in: Nano Energy


Publication date: April 2018 Source:Nano Energy, Volume 46 Author(s): Zhenghui Pan, Huozhen Zhi, Yongcai Qiu, Jie Yang, Lidan Xing, Qichong Zhang, Xiaoyu Ding, Xianshu Wang, Guoguang Xu, Hua Yuan, Min Chen, Wanfei Li, Yagang Yao, Nunzio Motta, Meinan Liu, Yuegang Zhang Enabling fast ion diffusion in thick electrodes (100–200 µm, ~ 10 mg cm−2) is critical for their practical application in state-of-the-art supercapacitors (SCs). We developed a three-dimensional (3D) boron, nitrogen, and phosphorus ternary-doped holey graphene hydrogel (BNP-HGH) film to achieve an optimized porous structure with a high electrical conductivity, large ion accessible surface area, efficient electron and ion transport pathways, as well as high ion adsorption capacity. The binder-free BNP-HGH electrode can deliver a specific capacitance of 350 F g−1 and a volumetric capacity of 234 F cm−3, which are the best performance reported so far for graphene-based SCs using an organic electrolyte. Fully packaged SCs using the BNP-HGH electrodes with a commercial level graphene mass loading (150 µm, ~ 10 mg cm−2) can deliver ultrahigh stack gravimetric and volumetric energy densities of 38.5 Wh kg−1 and 57.4 Wh L−1, respectively, which are comparable to those of lead-acid batteries (35–40 Wh kg−1 and 50–90 Wh L−1) while maintaining an ultrahigh power density of 83 kW kg−1 (~ 55 kW L−1) as well as a long cycle life (81.3% capacitance retention over 50,000 cycles). The high energy and power densities bridge the gap between traditional SCs and batteries, and should be very useful in practical applications. Graphical abstract