Bio-inspired coral reef-like NiCo-LDH nanostructure fabricated on carbon felt for high performance flexible supercapacitor

Technological advancements have spurred an emerging demand for flexible energy storage devices with high-power density and significant cycle stability. Here, an environmentally-friendly approach has been developed to synthesize coral reef-bioinspired ultrathin NiCo layered double hydroxides (CRBI-LDH) composites on carbon felt (CF) substrates. The developed thin layer nanostructure, which consists of mesoporous ultrathin LDH nanosheet arrays vertically grown onto the surface of the flexible carbon felt fibers, mimics the natural architecture of coral reefs to create a highly efficient asymmetric supercapacitor. The CF/CRBI-NiCo-LDH electrode exhibited a remarkable specific capacitance of 1661.6 F g^-1 at the current density of 1 A g^-1, and it still retained a capacitance of 1617.6 F g^-1 even when the current density was increased to 10 A g^-1. Moreover, the CF/CRBI-NiCo-LDH revealed excellent cycling stability (96.7% retention after 3000 cycles). An excellent energy density of 57.2 Wh kg^-1 was also observed at a power density of 820 W kg^-1, when an asymmetric supercapacitor was employed with CRBI-NiCo-LDH nanocomposite as the cathode and activated carbon paste electrode as the anode. This combination of high performance, low cost, and ease of fabrication makes this approach promising for the development of flexible energy storage devices.