Green and Sustainable Hydroxyquinone Molecule Electrodes Prepared for Efficient Energy Storage

Organic electrode materials have been widely investigated for their high theoretical capacity, low toxicity, renewability, inexpensive cost, and chemical/structural tunable advantages. Herein, 2-hydroxyanthraquinone (HAQ)-reduced graphene oxide (rGO) hydrogel with a hierarchical porous structure was prepared to achieve more efficient energy storage. The optimal HAQ-rGO(0.5:1) composite can afford a high capacity of 325 F g-1 at 1 A g-1 and a good rate capability corresponding to 96.5% retention of the original after 10,000 cycles in a 1M H2SO4 electrolyte. Given the density functional theory (DFT) calculation, the binding energy of HAQ on rGO and the charge density difference of the stacking site under different adsorption directions were estimated. The cooperative effect is essential to boost the electrochemical behavior of supercapacitors. The constructed asymmetric supercapacitor (HAQ-rGO//BDTD-rGO) has a most energy density of 17.7 Wh kg-1, 0.7 kW kg-1, a Coulomb efficiency of 99%, and a long-term cycling stability (93% capacitance retention even after 10,000 cycles of 5 A g-1). In addition, 104 LEDs are lit in series with two HAQ-rGO//BDTD-rGO devices.