A Sol–Gel Process for Fabrication of NiO/NiCo₂O₄/Co₃O₄Composite with Improved Electrochemical Behavior for Electrochemical Capacitors

Abstract

Transition metal oxides possess multiple oxidation states that enable rich redox reactions for pseudo capacitanc. They have been investigated as promising electrode materials to achieve high energy density. In this study, NiO/NiCo(2)O(4)/Co(3)O(4) composite with high specific surface and mesoporous structure is fabricated by a sol-gel process then calcined at 250 °C. Benefits from the improved electron conductivity and effective mesoporous structure, the fabricated composite exhibits high specific capacitance (1717 F g(-1)), enhanced rate capability, and excellent electrochemical stability (94.9% retention after 1000 cycles). Interestingly, the specific capacitance of the composite is higher than that of NiO, NiCo(2)O(4), and Co(3)O(4), which indicates a synergistic effect of the composite on improvement of electrochemical performance. The findings demonstrate the importance and great potential of NiO/NiCo(2)O(4)/Co(3)O(4) composite in development of high-performance energy-storage systems.

Urchin and sheaf-like NiCo 2 O 4 nanostructures: Synthesis and electrochemical energy storage application

“…As a result it evinces promising electrochemical properties and could be an alternative pseudocapacitive material to RuO 2 [3,10]. Moreover, NiCo 2 O 4 can be synthesized with diverse structural morphologies such as nanowires [28,34,35], nanoflowers [36e38], nanorods [39], nanotubes [40], nanosheets [41], nanoneedles [42], nanoparticles [43,44] and nanoflakes [27] by hydrothermal, solvothermal, precipitation, solegel and microwave assisted methods [36,43,45]. These diverse structural morphologies of NiCo 2 O 4 have numerous potential applications in many fields such as electrocatalysis [38,46], lithium ion batteries [47], electrical transport [48], photocatalysis [49], photodetectors [50], magnetic materials [51], and quite extensively in electrochemical supercapacitors [27,28,31e37].…”

Liquid Phase Synthesis of CoP Nanoparticles with High Electrical Conductivity for Advanced Energy Storage

“…However, the energy density of supercapacitors (4-5 Wh kg −1 for carbon based supercapacitors) is still lower than batteries Wh kg −1 ) and prevents their practical applications [4,5]. Therefore, many researchers are focused on improving the energy density of supercapacitors while maintaining their high power density [6][7][8]. The energy storage of pseudocapacitors is based on the Faraday reactions occurring at the surface of electroactive materials, such as RuO 2 , MnO 2 , IrO 2 , and Co 3 O 4 [9][10][11][12][13], and the energy density is higher than carbon based electric double-layer capacitors.…”

An investigation of the electrochemically capacitive performances of mesoporous nickel cobaltite hollow spheres

“…Thirdly, NiCo 2 O 4 owns several inherent advantages, including low cost, abundant resources and good environmental benignity. These NiCo 2 O 4 usually show superior electrochemical performances as supercapacitor electrode materials compared with Co 3 O 4 and NiO [20][21][22]. The excellent electrochemical properties coupled with these attractive features above render NiCo 2 O 4 become a promising cost-effective and scalable alternative candidate for highperformance supercapacitors.…”