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.   

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