Redox-Active Xerogels As Pseudocapacitve Electrodes with Excellent Cycling Performance

Electrochemically active organic molecules are emerging materials for small- to large-scale energy storage applications due to their low cost, recyclability, safety, and low toxicity. 1,2 In addition, they are compatible with various conductive substrates and their electrochemical properties can be tuned using established organic chemistry principals. 3,4 However, their poor conductivity and degradation upon cycling hamper the development of redox-active molecules/polymers for supercapacitors. Among all electroactive molecules, quinone-functionality is especially attractive due to its fast 2 e - /2 H + redox reactions, and its ability to increase the capacitance of the double-layer capacitors. 1,5 Here, we synthesized conductive redox active xerogel by incorporating 2,5-dimethoxy-1,4-benzoquinone (DMQB) on reduced graphene oxide (rGO) sheets via hydrothermal method. The physisorbed DMQB on rGO sheets via π-π stacking interactions was characterized via various spectroscopic and electrochemical methods. DMQB anchored rGO sheets exhibited high gravimetric capacitance of 1100 F/g, which exceeded pristine rGO sheets by the factor of five. Furthermore, DMQB@rGO based electrodes showed negligible IR drop, low ESR values and good columbic efficiency. Most importantly, electrodes showed negligible capacitance loss when cycled up to 25,000 cycles. 1. B. Huskinson et al., Nature , 505 , 195–8 (2014). 2. K. B. Hatzell, M. Boota, E. C. Kumbur, and Y. Gogotsi, J. Electrochem. Soc. , 162 , A5007–A5012 (2015). 3. M. Boota, K. B. Hatzell, E. C. Kumbur, and Y. Gogotsi, ChemSusChem , 8 , 835–843 (2015). 4. S. E. Burkhardt et al., Energy Environ. Sci. , 5 , 7176 (2012). 5. D. Vonlanthen, P. Lazarev, K. a. See, F. Wudl, and A. J. Heeger, Adv. Mater. , 26 , 5095–5100 (2014).