Eco-friendly synthesis of hierarchical ginkgo-derived carbon nanoparticles/NiAl-layered double hydroxide hybrid electrodes toward high-performance supercapacitors

Abstract

Three-dimensional carbon nanoparticles (CPs)/Ni–Al layered double hydroxide (NiAl-LDH) (CP/LDH) hybrids with hierarchical nanostructures have been facilely prepared with NiAl-LDH nanosheets homogeneously located on the surface of CPs through an in situ hydrothermal growth process. Eco-friendly synthesized from the fallen ginkgo leaves, CPs with mesoporous architecture are chemically activated and used as building blocks for the construction of hierarchical CP/LDH hybrids. Mesoporous CPs coupled with the NiAl-LDH nanosheets are favorable to improve the mass transfer, adsorption/desorption of ions, as well as the electrochemical performance of the electrodes. The electrochemical measurements show that CP/LDH hybrid exhibits a remarkably enhanced specific capacitance of 1355 F g⁻¹ at 5 mV s⁻¹, compared with 121 F g⁻¹ of CPs and 405 F g⁻¹ of pure NiAl-LDHs, as a result of the synergistic effect from electrochemical double layer capacitance of CPs and pseudocapacitance of NiAl-LDHs. Furthermore, the CP/LDH hybrid shows excellent rate capability and good long-term cycling performance with 90% capacitance retained after 2000 cycles. Therefore, the facilely prepared CP/LDH hybrids are promising electrode materials for potential applications in energy storage devices.