Biomass‐Derived Carbon Quantum Dots‐Induced Self‐Assembly of 3D Networks of Nickel‐Cobalt Double Hydroxide Nanorods as High‐Performance Electrode Materials for Supercapacitors

Abstract The nickel‐cobalt double hydroxide hybrid materials induced by biomass‐derived carbon quantum dots (CQDs) have a three‐dimensional network structure of cross‐linked nanorods. The results demonstrate that the functional groups on the CQDs derived from pomelo peel promoted the nucleation and confined the growth of nickel‐cobalt double hydroxide. The as‐synthesized NiCo‐LDH‐CQDs‐20 exhibits the high specific capacitance of 1814 F g −1 at 1 A g −1 . When the current density is increased to 15 A g −1 , the specific capacitance value remains 75.5 % of the initial one, which indicates that NiCo‐LDH‐CQDs‐20 has an extremely high‐rate performance. Furthermore, the asymmetric supercapacitor NiCo‐LDH‐CQDs‐20//AC provides a high energy density of 46.47 Wh kg −1 in 2 M KOH solution with a power density of 800 W kg −1 and maintains an initial specific capacitance of 82.7 % after 2000 cycles. Therefore, this study provides a promising approach for the development of anode active materials in supercapacitor energy storage devices.