Robust, Environmentally Benign Synthesis of Nanoporous Graphene Sheets from Biowaste for Ultrafast Supercapacitor Application

Abstract

In this study, we adopted a simple method to synthesize a graphene-like-structured nanoporous carbon using a jute stick as a carbon precursor and studied the electrochemical properties for supercapacitors. The synthesized nanoporous carbon is composed of a graphene sheet-like network and amorphous carbon, and the ratio between these two components is tuned by the activation temperature. As the activation temperature is increased, the amorphous carbon is converted into a stable graphene-like network with a high specific surface area of 2396 m2/g, with a graphene sheet-like morphology and a highly ordered graphitic sp2 carbon. For supercapacitor application, the nanoporous carbon is studied in aqueous as well as organic electrolytes, and the material shows excellent electrochemical performance in both the cases. It exhibited a high specific capacitance of 282 F/g and shows excellent rate capability with almost 70% capacitance retention at high current rates. Furthermore, the assembled symmetric supercapacitor displays a remarkable energy density of 20.6 W h kg–1 at a high power density of 33 600 W kg–1, and the benchmark studies revealed that the nanoporous carbon developed in the present study is better than the commercially available supercapacitive carbon (YP-50 F). A cylindrical supercapacitor device of capacitance 20 F with 2.7 V was fabricated using the nanoporous carbon electrode and tested for running practical devices. The excellent electrochemical performance of the electrode material can be attributed to the high electrical conductivity of the ordered graphene network coupled with high specific surface area and optimum pore size distribution of nanoporous carbon. These results demonstrate a facile, low-cost, and eco-friendly design of materials for energy storage applications.

Jute sticks derived novel graphitic porous carbon nanosheets as Li‐ion battery anode material with superior electrochemical properties

“…The narrow and broad diffraction peaks appear at 2θ = 25.9 o and 2θ = 43.4 o corresponds to the presence of (002) and (101) reflections of graphite (JCPDS card no. 41‐1487), respectively . The sharp and narrow (002) diffraction peak appears at 2θ = 25.9 o implies the high crystalline nature of carbon material developed in the present study.…”

“…41-1487), respectively. 1,12 The sharp and narrow (002) diffraction peak appears at 2θ = 25.9 o implies the high crystalline nature of carbon material developed in the present study. To evaluate the ordered and disordered structures and the number of graphene layers in the material, Raman spectroscopic measurement is carried out and the resulting spectrum is shown in Figure 3B.…”

“…Both XRD and Raman results concluded that the synthesized carbon material is more of graphitic nature, which is expected to improve the charge‐transfer rate characteristics of electrode material in delivering good electrochemical performance as graphitic nature enhances the electrical conductivity of carbon material. The N 2 adsorption‐desorption isotherm in Figure 4A clearly exhibits a type IV isotherm, characteristics of mesoporous nature of the carbon material and a slight sharp raise of N 2 uptake at low relative pressure (<0.3 P/Po), reveals the presence of micropores . The specific surface area and pore volume of GPCS carbon material is around 1246 m 2 g ‐1 and 0.86 cm 3 g ‐1 , respectively.…”

“…High specific surface area porous carbon materials were synthesized by chemical activation in our previous work for supercapacitor application by employing a high concentration of activation agent . In this work, for synthesis of GPCS material, 2 gms of carbonized powder of jute stick was mixed with 6 gms of KOH and activated at 900°C in argon atmosphere by heating the sample at a rate of 5°C/min for 1 hr.…”

“…High specific surface area porous carbon materials were synthesized by chemical activation in our previous work for supercapacitor application by employing a high concentration of activation agent. 12 In this work, for synthesis of GPCS material, 2 gms of carbonized powder of jute stick was mixed with 6 gms of KOH and activated at 900°C in argon atmosphere by heating the sample at a rate of 5°C/min for 1 hr. After activation, the resulting material was thoroughly washed with 1M hydrochloric acid and DI water to get rid of any metal impurities, until it reached a neutral pH and then dried the sample at 100°C to obtain Graphitic porous carbon sheets (GPCS).…”