Asymmetric supercapacitor based on reduced graphene oxide/MnO2 and polypyrrole deposited on carbon foam derived from melamine sponge

Carbon sponges enclosing carbon fibers are prepared by carbonizing the melamine sponges with bunches of carbon fibers sewn in, and used as the substrate and current collector to fabricate asymmetric supercapacitors. MnO2/rGO/CS-CFs as the positive electrode and the PPy/CS-CFs as the negative electrode have been prepared and characterized, and in LiCl/polyvinyl alcohol gel electrolyte, the positive and negative electrodes are used to fabricate the asymmetric supercapacitors. The cells exhibit an operating voltage window of 1.4 V and high specific capacitance of 106.1 F g(-1) based on the active materials and high cyclic stability (83.7% capacitance retention after 10000 cycles). The asymmetric supercapacitors in parallel and series connection show good electrical relationships, and two cells in series connection can turn on a light emission device after being charged, indicating the potential practical application.