Bio-template Synthesis of Three-Dimensional Microtubular Nickel-Cobalt Layered Double Hydroxide Composites for Energy Storage

Three-dimensional hollow microtubular nickel-cobalt layered double hydroxide composites were facilely fabricated by controlling the growth on the external and internal surface of natural kapok fibers. The incorporation of kapok fibers induced the confined growth of nickel-cobalt layered double hydroxide on the kapok fiber templates, and the tubular structure of the composite did not collapse with the extension of the hydrothermal time. The obtained unique structure was in favor of enhancing the electrochemical properties of nickel-cobalt hydroxide. The composites prepared after reaction for 8 h exhibited the maximum specific capacity of 1112.25 C g−1 at current density of 0.5 A g−1. Coupled with the active carbon negative electrode, the assembled hybrid supercapacitor device delivered a maximum energy density of 38.0 W h kg−1 with an operational voltage of 1.6 V.