Sea Urchin-Like NiCo-LDH Hollow Spheres Anchored on 3D Graphene Aerogel for High-Performance Supercapacitors

To enhance the inherent poor conductivity and low cycling stability of dimetallic layered double hydroxides (LDHs) materials, designing a synergistic effect between EDLC capacitors and pseudocapacitors is an efficient strategy. In this paper, we utilized a solvothermal technique employing Co-glycerate as a precursor to prepare sea urchin-like NiCo-LDH hollow spheres anchored on a 3D graphene aerogel. The unique morphology of these hollow microspheres significantly expand the specific surface area and exposes more active sites, while reducing the volume changes of materials during long-term charging and discharging processes. The 3D graphene aerogel serves as a conductive skeleton, improving the material's electrical conductivity and buffering high current. The sea urchin-like NiCo-LDH hollow spheres anchored on 3D graphene aerogel (H-NiCo-LDH@GA) has a specific surface area of 51 m² g^-1 and the I_D/I_G value is 1.02. The H-NiCo-LDH@GA demonstrate a significant specific capacitance of 236.8 mAh g^-1 at 1 A g^-1, with a remarkable capacity retention rate of 63.1 % even at 20 A g^-1. Even after 8000 cycles at 10 A g^-1, the capacity retention still remains at 96.3 %, presenting excellent cycling stability.