Rapid and Facile Method for the Synthesis of a Nanoarray Hierarchical Composite and Its Application in Flexible Self-Chargeable Supercapacitors

In this paper, a 3D nanoarray hierarchical composite composed of graphene nanoscroll (GNS) and nickel–cobalt layered double hydroxide (NiCo-LDH) nanoplates was successfully constructed on carbon cloth (CC) by electrophoretic deposition and subsequent electrodeposition, in which the NiCo-LDH nanoplates were vertically aligned on the GNS. Owing to the combined advantages of 1D GNS for boosting the charge transport and preventing stacking, 2D NiCo-LDH nanoplates for increasing the capacitance and improving the mechanical stability, and the 3D carbon cloth substrate for providing electrical conductivity and flexibility, the NiCo-LDH/GNS@CC electrode exhibited a high areal capacitance of 2529.8 mF·cm–2 and a capacitance retention of 101.28% even after 10,000 cycles. Moreover, the as-assembled flexible symmetric supercapacitor (FSSC) device provided an areal capacitance of 603.8 mF·cm–2 at 1 mA·cm–2. Notably, the FSSC achieved an energy density of 195.54 μW h cm–2 when the power density was 0.76 mW·cm–2. The device also demonstrated good flexibility, structural stability, and water resistance. Additionally, a flexible self-chargeable pack (FSCP) was assembled by integrating the fabricated flexible supercapacitor with a flexible solar cell panel to demonstrate its promising application in real-world electronic devices.