Construction of NiCo-LDH vertical standing arrays on carbon fibers for highly effective supercapacitors and catalytic oxygen evolution applications

Layered double hydroxides (LDH) have attracted a lot of attention in the field of energy storage and energy conversion due to their unique properties. However, it is still challenging to obtain LDH electrode materials with efficient energy storage and electrocatalytic properties simultaneously. In this work, NiCo-LDH with a vertical standing form was grown on defect-rich carbon fibers through an in-situ growth strategy to obtain a bifunctional self-supporting electrode with an "organ-pipe cactus"-like structure. This three-dimensional structure not only ensures high quality loading of NiCo-LDH nanomaterials, but also allows close contact between the active material and the conductive substrate, which greatly shortens the ion diffusion path. The prepared NiCo-LDH@CC self-supported electrode exhibits excellent cycling stability with a capacitance retention rate of 93% after 8000 cycles at 15 A g -1 . In addition, the NiCo-LDH@CC composite has an ultra-low oxygen precipitation overpotential of 372 mV at 10 mA cm -2 , which is superior to most reported non-precious metal-based bifunctional catalysts. These results suggest that the design of NiCo-LDH@CC self-supporting electrodes offers new ideas for the realization of efficient multifunctional nanomaterial applications. Structural differences of layered double hydroxide with different morphologies are reported to help advance applications in energy storage and conversion. • Bimetal LDH composites are used for supercapacitor and catalytic oxygen evolution. • Vertical standing NiCo-LDH@CC arrays is obtained as self-supporting electrodes. • The properties of LDHs are improved by regulating pore size distribution. • NiCo-LDH//AC flexible supercapacitor has energy density up to 20.7 W h kg -1 . • Current density decrease rate of NiCo-LDH is 0.127 mA cm -2 h -1 after catalysis.