Selective synthesis of hierarchical mesoporous spinel NiCo2O4 for high-performance supercapacitors

Abstract

Hierarchical mesoporous spinel NiCo₂O₄ was synthesized by a facile hydrothermal method assisted by polyvinylpyrrolidone (PVP) and a post annealing treatment. The synthesized hierarchical mesoporous NiCo₂O₄ presents a hierarchical mesoporous structure with diameters of 5.0 and 25 nm, respectively. Compared to conventional flower-like NiCo₂O₄, the hierarchical mesoporous structured NiCo₂O₄ exhibits excellent supercapacitor performance. The specific capacitance can reach 1619.1 F g(-1) at a current density of 2.0 A g(-1). When the current density is increased to 10.0 A g(-1), a specific capacitance of 571.4 F g(-1) can be obtained. Furthermore, the hierarchical mesoporous structured NiCo₂O₄ presents excellent stability. The outstanding electrochemical performance of the hierarchical mesoporous NiCo₂O₄ reveals its potential to be a promising material for use in supercapacitors, and also inspires continued research on binary metal oxides as energy transformation materials.

Heterogeneous NiCo2O4@polypyrrole core/sheath nanowire arrays on Ni foam for high performance supercapacitors

“…5a shows the CV cures of pristine NiCo 2 O 4 and NiCo 2 O 4 @PPy in the potential ranging from 0 to 0.6 V at the scan rate of 5 mV s À1 in 6 M KOH solution. For the NiCo 2 O 4 , a pair of redox peaks at 0.28 and 0.45 V (vs. Hg/HgO) are clearly observed, which corresponds to the reversible reactions of Co 3þ /Co 4þ and Ni 2þ /Ni 3þ transitions associated with anions OH À [44,45]. …”

Hybrid NiCo2S4@MnO2 heterostructures for high-performance supercapacitor electrodes

“…9 In addition, the binary Ni-Co sulfides, similar to the binary Ni-Co oxides have been reported, which possesses higher electrochemical activity in supercapacitors than nickel sulfides and cobalt sulfides. 10 around to overcome the drawbacks and to improve its electrochemical performance. [17][18][19] whole experiment.…”

Mesoporous NiCo2O4 nanoneedles grown on three dimensional graphene networks as binder-free electrode for high-performance lithium-ion batteries and supercapacitors

“…As one of the most promising metal oxides for LIBs and SCs, spinel nickel cobaltite (NiCo 2 O 4 ), possessing the advantages of high theoretical capacitance/capacity, intriguing electronic conductivity, easy-preparation, abundant resources and environmental friendliness, has been mostly investigated [23][24][25][26]. Considerable efforts have been made to improve the electrochemical performances of NiCo 2 O 4 for LIBs and SCs by adjusting the morphologies, such as nanowires [27,28], nanosheets [29], nanotubes [25], and microspheres [30,31], etc.…”