Quinone materials for supercapacitor: Current status, approaches, and future directions

Supercapacitor, an energy storage device, has received much attention in recent years. The construction of supercapacitor devices with a suitable anode, cathode, and electrolyte materials plays a vital role in commer-cialization. In this direction, quinones are being used as electroactive materials in the last two decades. Carbon-quinones are considered to be the most promising materials and capable of increasing the performance of electrochemical capacitors. This review provides a clear idea about the classification of supercapacitors based on the use of electrodes, electrolytes, and their mechanisms, device configurations. The performances of the supercapacitors with carbon-quinone composites used as electrodes in the literature are reviewed. The effect of the incorporation of quinones with various carbon materials via physical adsorption, impregnation, grafting, solvent-free, solvothermal, wet chemistry, hydrothermal, and reflux methods in the overall performance of supercapacitors are discussed. In summary, the advantages of the use of quinones in a supercapacitor, the drawbacks associated with these materials, and future directions towards commercialization are brought out.