Layered Assembly of Reduced Graphene Oxide and Vanadium Oxide Heterostructure Supercapacitor Electrodes with Larger Surface Area for Efficient Energy-Storage Performance

The architecture of a supercapacitor (SC) electrode plays a crucial role in defining the overall energy-storage performance of the SC. Layer-by-layer assembly of a reduced graphene oxide (rGO) and vanadium oxide (V2O5) (rGO/V2O5)-based heterostructure is patterned in interdigitated electrodes (IDEs) deposited directly on a flexible conducting current collector for the SC. The IDE pattern offers efficient accessibility to the electrolyte ions and a synergistic contribution for energy storage. An as-fabricated solid-state flexible sandwich-type SC with IDEs displays a more efficient energy-storage performance than a conventional solid-state flexible sandwich-type SC composed of rGO/V2O5 electrodes. Moreover, a solid-state flexible in-plane microsupercapacitor (MSC) is fabricated, which offers much higher capacitance (24 mF/cm2 and 34.28 F/cm3) and energy density (3.3 μWh/cm2 and 4.7 mWh/cm3). The as-fabricated flexible in-plane MSC displays a negligible capacitance loss of about 6.3% after 10 000 charge–discharge cycles and a superior stability of energy-storage performance towards mechanical deformation.