Hierarchical 3D Cobalt‐Doped Fe₃O₄ Nanospheres@NG Hybrid as an Advanced Anode Material for High‐Performance Asymmetric Supercapacitors

Abstract

Hierarchical nanostructure, high electrical conductivity, extraordinary specific surface area, and unique porous architecture are essential properties in energy storage and conversion studies. A new type of hierarchical 3D cobalt encapsulated Fe O nanosphere is successfully developed on N-graphene sheet (Co-Fe O NS@NG) hybrid with unique nanostructure by simple, scalable, and efficient solvothermal technique. When applied as an electrode material for supercapacitors, hierarchical Co-Fe O NS@NG hybrid shows an ultrahigh specific capacitance (775 F g at a current density of 1 A g ) with exceptional rate capability (475 F g at current density of 50 A g ), and admirable cycling performance (97.1% capacitance retention after 10 000 cycles). Furthermore, the fabricated Co-Fe O NS@NG//CoMnO @NG asymmetric supercapacitor (ASC) device exhibits a high energy density of 89.1 Wh kg at power density of 0.901 kW kg , and outstanding cycling performance (89.3% capacitance retention after 10 000 cycles). Such eminent electrochemical properties of the Co-Fe O NS@NG are due to the high electrical conductivity, ultrahigh surface area, and unique porous architecture. This research first proposes hierarchical Co-Fe O NS@NG hybrid as an ultrafast charge-discharge anode material for the ASC device, that holds great potential for the development of high-performance energy storage devices.

Construction of SnS2–SnO2 heterojunctions decorated on graphene nanosheets with enhanced visible-light photocatalytic performance

“…The spectrum of C 1s, as shown in Fig. 3(b), displays binding energies at 284.5, 285.6 and 286.8 eV, which are assigned to C-C, C-O and C O, respectively (Guo et al, 2017). The decreased intensity of the carbon binding to oxygen in the sample suggests that most oxygen-containing functional groups in layered graphene oxide have been reduced to RGO.…”

Flocculant-Assisted Synthesis of Graphene-Like Carbon Nanosheets for Oxygen Reduction Reaction and Supercapacitor

“…The NSC-Fe-2 showed outstanding capacitive behavior, and the specific capacity was 195 F g −1 at 1 A g −1 , as can be seen from Figure 6d. The symmetrical GCD curves at various current densities clearly demonstrate the ideal capacitive characteristic of NSC-Fe-2 [48]. Figure 6e displays the capacitance retention of NSC-Fe- x at different current densities.…”

Raman spectroscopy and correlative‐Raman technology excel as an optimal stage for carbon‐based electrode materials in electrochemical energy storage

“…It was proved that Fe 2 O 3 and CNT-GF are composited successfully. Guo et al [59] also analyzed the structure of Co-Fe 3 O 4 NS@NG (cobalt encapsulated Fe 3 O 4 nanosphere is developed on N-graphene sheet) by Raman spectroscopy. The Raman characteristic peak of Fe 3 O 4 (≈200-800 cm À1 ) showed that the complex was successfully synthesized.…”