NiC2O4 nanorods embellished NiCo layered double hydroxide nanoflowers with enhanced electrochemical performances for hybrid supercapacitor

Designing and constructing a high performance and multi-component nickel-based material is preferable for efficient energy storage devices. In this study, we reasonably designed a composite material, NiC2O4/NiCo layered double hydroxide (LDH), composed of 1D NiC2O4 nanorods and 3D NiCo-LDH nanoflowers self-assembled from nanosheets via a hydrothermal method. This causes NiCo-LDH nanoflowers to stretch out, increasing the specific surface area (up to 47 m2 g−1), improving contact with the electrolyte and providing abundant active sites, speeding up the transfer of protons. The excellent double redox reactions of NiC2O4 and NiCo-LDH expedite the reaction kinetics and boost electrochemical activities, resulting in high energy densities of 37.6 Wh kg−1 and high power densities of 809.8 W kg−1 for the NiC2O4/NiCo-LDH||AC hybrid supercapacitor devices. Furthermore, DFT calculations indicate NiC2O4/NiCo-LDH enhance the adsorption ability of OH−. And the improved electrochemical performance of NiC2O4/NiCo-LDH is due to partial electrons transfer through the interface.