3D-Interconnected Channels of Ordered Mesoporous Carbon (3D-OMC) : Effective Electrode Material for Electrochemical Supercapacitors
Authors: Arulmani S , Suresh C , Sivakumar C 
Published: February 2020

Alarming of global climate change by increasing strategy of atmospheric CO2 emissions and dwindling of fossil fuel leads to energy associated queries in near future. For complementary, generation/utilization of alternate energy is an important promise. Different type of energies (conventional/non-conventional) were developed that can meet the present day power demands. Batteries, fuel cells and supercapacitors are the best candidates for storing/conversion of the generated energy.1

In modern days supercapacitors have much more attention than others because of its high power density, slow discharging capacity with ultra fast charging and good cycling stability with high capacitance retention. In addition light weight, flexibility and effective performance in energy storage it is focused for future in backup power systems, electric vehicles and electronic components. The electric double layer formed at the interface between an electronically conductive material and an electrolyte solution is the basic mechanism for charge storage performance.1,2 Carbon and its allotropes like CNT, graphene etc., plays a major role in supercapacitors fabrication due to their unique structural morphology, excellent conductivity and electrochemical stability. The controlled morphology, high surface area with porous nature may increase the easy accessibility of electrolyte.3,4Herein, we report the 3D-interconnected channels of ordered mesoporous carbon (3D-OMC) as an electrode material for electrochemical supercapacitors with enhanced performance over with Vulcan carbon.
In the present study, 3D-OMC was synthesized by using mesoporous silica KIT-6 as template and sucrose was used as carbon source. The as synthesized material was characterized with Low angle XRD (crystanallity), Laser Raman (microstructure), BET (surface area), SEM & TEM (Morphology) and AFM (topography). From all the above, the 3D-OMC has IG/IDratio of 1.06, surface area, pore volume and average pore size as 750 m²/g, 0.88 cm³/g and 4.6 nm respectively with well arranged porous network of 3D-carbon. Electrochemical studies of the synthesized material was investigated by cyclic voltammetry (CV) and Galvanostatic Charge-Discharge cycle test in acidic medium and made comparison over with Vulcan carbon (VC).
The existence of typical rectangular-shaped voltammogram reveals that an ideal electrical double layer capacitor (EDLC) behavior arisen from the charge accumulation at electrode/ electrolyte interface. Eventhough both materials shows the EDLC, the integrated area of the rectangular shape of 3D-OMC electrode was high compared to VC due to the pours nature and the ability towards interaction between electrolyte. On account of the encircled area of CV, current density increases with a gradual increase of scan rate (5 to 300 mV) reveals a superior specific capacitance as a result of major involvement of EDLC mechanism. In addition a couple of wide and vague peaks were observed from the faradic redox reactions (pseudo-capacitance) that performed due to the involvement of oxygen-containing groups on the carbon surface.3,5

The discharge (linear voltage versus time) profile of 3D-OMC shows a superior symmetrical charge/discharge performance than VC. Specific capacitance of the 3D-OMC (206 F/g) is higher when compared with VC (58 F/g) at 0.5 A/g and also shows a good cycling stability with high retention. Hence the enhanced specific capacitance of 3D-OMC is considered one of the most promising materials for electric double layer capacitors (EDLC) for future energy storage applications.

References

1. M. Winter and R. J. Brodd, Chem. Rev., 104, 4245–4269 (2004)
2. M. D. Stoller and R. S. Ruoff, Energy Environ. Sci., 3, 1294 (2010)
3. V. Georgakilas, J. A. Perman, J. Tucek, and R. Zboril, Chem. Rev., 115, 4744–4822 (2015)
4. P. Simon and Y. Gogotsi, Nat. Mater., 7, 845–854 (2008).
5. Q. Li, R. Jiang, Y. Dou, Z. Wu, t. haung, D. Feng, J. Yang, A. Yu and D. Zhao, Carbon N. Y., 49, 1248–1257 (2011)

Figure 1