Jatropha Oil Cake Based Activated Carbon for Symmetric Supercapacitor Application: A Comparative Study on Conventional and Hydrothermal Carbonization Processes

Abstract

Jatropha oilcake (JOC), a major agro industrial co-product was effectively converted into activated carbons employing KOH mediated chemical process for supercapacitor applications. The activated carbons were synthesized by employing conventional (CC) as well as hydrothermal carbonization (HTC) processes and investigated their impact on their physicochemical properties. The graphitization degree of the pristine and activated biocarbons was investigated through XRD and RAMAN analysis. BET surface area analysis showed the enhanced specific surface area of the pristine carbons from 71.5 (CC) and 48.1 (HTC) m 2 /g into 678.1 (CC) and 746.7 m 2 /g (HTC) through KOH activation. The synthesized activated biocarbon materials were explored as the electrode material for supercapacitors. The electrochemical analysis of the fabricated symmetric supercapacitor showed the specific capacitance of 145.76 F/g and 174.78 F/g at 1 A/g for the activated biocarbons obtained respectively through conventional and hydrothermal carbonization processes. Also, they showed considerable energy density of 5.28 Whkg À 1 (CC) and 6.49 Whkg À 1 (HTC) at a power density of 248.6 and 265.09 W kg À 1 . Among the two different approaches, the hydrothermal process showed great promise for the production of renewable biomass-derived activated biocarbon materials for supercapacitor applications.

A Review of Supercapacitors: Materials Design, Modification, and Applications

“…The synthesized composite showed high specific capacitance, porosity and conductivity and found to be a promising electrode material for use in supercapacitors. Furthermore, porous carbon [190], bamboo fibers [191], Jatropha oil cake-based activated carbon [192], birnessite-type MnO 2 /carbon [193], palm oil-based supercapacitor [194], Co/MnO/CoMn 2 O 4 @RHs [195], polythiophene (PTh) nanofibers [196], hierarchical porous carbons (HPCs) [126], and porous carbons derived from laminaria japonica [190] were used as electrode materials in supercapacitors, which were synthesized through carbonization technique. Figure 11 represents a schematic illustration of the synthesis of porous carbons derived from Laminaria japonica.…”

Oil Cakes as Sustainable Agro‐Industrial Feedstock for Biocarbon Materials

“…The activated carbon obtained through the thermal activation process showed the highest specific surface area of 904.72 m 2 g −1 . We have also reported the fabrication of activated carbon from jatropha oil cake utilizing conventional and hydrothermal carbonization processes through KOH enabling the chemical activation process 135. The specific surface areas of the activated biocarbon materials achieved at 800 °C by conventional and hydrothermal carbonization were found to be 678.1 and 746.7 m 2 g −1 , respectively.…”

“…HTC processes are extensively applied for the conversion of different types of biomasses into carbon products; however, the conversion of oil cake residues into biocarbon materials has not been explored as much. Only the oil cakes of rapeseed 78, jatropha 135, Pongammia pinnata , and tung 99 were investigated for hydrothermal conversion into biocarbon materials. It was found that the activated biocarbon produced through HTC showed a higher specific surface area compared to the respective conventional carbonization process.…”

“…Oil cakes of safflower 103, soybean 94, pongamia 95, mustard cake 123, olive 105, rape seed 114, gingelly 120, cottonseed 126, jatropha 133, and karanja seed 135 were effectively converted into activated carbon by chemical activation processes using ZnCl 2 , KOH, K 2 CO 3, Na 2 CO 3 , and H 3 PO 4 as activating agents. The specific surface areas of the activated carbon through chemical activating processes are given in Tab.…”

“…Many oil cake resources have not yet been explored for energy storage applications like environmental remediation and catalysis. Our group also evaluated the jatropha oil cake‐derived pristine and activated biocarbon materials for supercapacitor applications 135. It was found that the symmetric supercapacitor fabricated with the activated biocarbon obtained through HTC process exhibited superior specific capacitance over the respective conventional carbonization process.…”