Scalable Asymmetric Supercapacitors Based on Hybrid Organic/Biopolymer Electrodes

A trihybrid bioelectrode composed of lignin, poly(3,4‐ethylenedioxythiophene) (PEDOT), and poly(aminoanthraquinone) (PAAQ) is prepared by a two‐step galvanostatic electropolymerization, and characterized for supercapacitor applications. Using PEDOT/Lignin as a base layer, followed by the consecutive deposition of PAAQ, the hybrid electrode PEDOT/Lignin/PAAQ shows a high specific capacitance of 418 F g−1 with small self‐discharge. This trihybrid electrode material can be assembled into symmetric and asymmetric supercapacitors. The asymmetric supercapacitor uses PEDOT + Lignin/PAAQ as positive electrode and PEDOT/PAAQ as negative electrode, and exhibits superior electrochemical performance due to the synergistic effect of the two electrodes, which leads to a specific capacitance of 74 F g−1. It can be reversibly cycled in the voltage range of 0–0.7 V. More than 80% capacitance is retained after 10 000 cycles. These remarkable features reveal the exciting potential of a full organic energy storage device with long cycle life. In order to avoid the mismatch between power production and electricity demand, the solar energy accessible by photovoltaic cells is coupled with the asymmetric supercapacitor based on PEDOT + Lignin/PAAQ and PAAQ/PEDOT biohybrid electrodes. This supercapacitor device gives the specific capacitance of 75 F g−1 and exhibits excellent cyclic stability with capacity retention of 80% by the end of 10 000 cycles.