All-Solid-State Symmetric Supercapacitor Based on Co₃O₄ Nanoparticles on Vertically Aligned Graphene

Abstract

We have synthesized the hybrid supercapacitor electrode of Co3O4 nanoparticles on vertically aligned graphene nanosheets (VAGNs) supported by carbon fabric. The VAGN served as an excellent backbone together with the carbon fabric, enhancing composites to a high specific capacitance of 3480 F/g, approaching the theoretical value (3560 F/g). A highly flexible all-solid-state symmetric supercapacitor device was fabricated by two pieces of our Co3O4/VAGN/carbon fabric hybrid electrode. The device is suitable for different bending angles and delivers a high capacitance (580 F/g), good cycling ability (86.2% capacitance retention after 20 000 cycles), high energy density (80 Wh/kg), and high power density (20 kW/kg at 27 Wh/kg). These excellent electrochemical performances, as a result of the particular structure of VAGN and the flexibility of the carbon fabric, suggest that these composites have an enormous potential in energy application.

Recent progress in carbon-based nanoarchitectures for advanced supercapacitors

“…Similarly, the hybrid electrode materials of Co 3 O 4 nanoparticles on vertically oriented graphene nanosheets upheld by carbon fabric were successfully synthesized, exhibiting an excellent electrochemical performance (Fig. 4d-f) [111]. Zhang et al [117] fabricated the α-Fe 2 O 3 /graphene nanocomposites through the solvothermal method and subsequent annealing treatment.…”

“…The excellent conductivity of graphene layers could omit the use of conductive additives, making graphene-based electrodes show improved energy density [107]. Owing to the strong cohesive van der Waals energy and intensive π-π interaction between the planar basal planes, however, graphene layers exhibit the strong tendency to restack together, which arises at stages in both electrode manufacture and cycling, and this may significantly decrease the ion-accessible surfaces and limit ion and electron transport due to narrower channels, strongly reducing the practical surface available for charge storage [106,111,112]. Therefore, to explore the approaches for the mitigation of these detrimental effects is essential.…”

“…Therefore, to explore the approaches for the mitigation of these detrimental effects is essential. Hitherto, numerous strategies have been explored to impede the aggregation of graphene layers so as to increase surface area, reduce the inner resistance, and facilitate the dispersal of electrolyte to the internal part of the electrode when assembled to a SC [107,111].…”

A Facile One-Pot Method for Co3O4/Graphene Composite as Efficient Electrode Materials for Supercapacitors

“…Second, the above composites were heat treated at 350-450 C and Co 3 O 4 /graphene composites were achieved. [11][12][13][14][15] The main drawback of the above two-steps method is that it is cobaltous hydroxide which was in situ located on the graphene sheets, rather than Co 3 O 4 . Moreover, somewhat aggregation of graphene was induced during drying and heat treatment of the composites, which might decrease the electrochemical performance of composites.…”

All-solid-state supercapacitors on silicon using graphene from silicon carbide

“…There is currently an increasing demand for compact and efficient energy storage solutions to match the rapid development of portable and wearable electronic products. [1][2][3][4][5] Miniaturized supercapacitors, as compared to battery technologies, are a preferable solution as they have an ultrafast charge/discharge capability, a high power density, and a long operating life. 6,7 However, conventional supercapacitors may suffer from liquid electrolyte leakage and incompatibility with miniaturization.…”