Lignin-derived carbon membrane for the preparation of composite electrodes and applications in supercapacitors

In order to obtain high performance, economic and environmentally friendly supercapacitor electrodes, lignin is converted into lignin-based phenolic resin and spun with polyvinyl alcohol (PVA) to obtain lignin-derived carbon membrane (LCM). Then LCM is used as substrate, and α-Fe2O3/LCM and LCM@ppy-10 composite materials are prepared as positive and negative electrodes, respectively, of supercapacitor electrodes. The results show that the composite electrodes have excellent electrochemical performance. At the current density of 1 mA cm−2, α-Fe2O3/LCM and LCM@ppy-10 show a high area specific capacitance of 487 mF cm−2 and 440 mF cm−2, respectively. The capacitance of the symmetrical button cells assembled by each electrode almost shows stability after 5000 cycles. In different systems, such as asymmetric aqueous supercapacitor and solid-state asymmetric supercapacitor, the composite electrodes also have excellent performance. The voltage of asymmetric supercapacitors is 1.6 V with area specific capacitance of 101 mF cm−2 at 1 mA cm−2. After 10,000 cycles at 2 mA cm−2, the specific capacitance decreases by only 5 %. The area specific capacitance and volume specific capacitance of solid-state asymmetric supercapacitor is 89 mF cm−2 and 1.74 F cm−3, respectively, at 1 mA cm−2. The maximum energy density and maximum power density of the solid-state asymmetric supercapacitor can reach 0.62 mWh cm−3 and 77.2 mW cm−3. This method can provide a new reference for the preparation of composite electrode with LCM as current collector.