“Green” carbon with hierarchical three dimensional porous structure derived from - Pongamia pinnata seed oil extract cake and NiCo2O4-Ni(OH)2/Multiwall carbon nanotubes nanocomposite as electrode materials for high performance asymmetric supercapacitor

• Published in: Journal of power sources Vol. 356; pp. 212 - 222
• Main Authors: Chaitra, K., Narendra, Reddy, Venkatesh, Krishna, Nagaraju, N., Kathyayini, Nagaraju
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2017
• Subjects: Asymmetric device; Energy density; Green carbon; Hierarchical porosity; Nanocomposite; Power source; Green carbon; Hierarchical porosity; Power source; Asymmetric device; Energy density; Nanocomposite
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2017.04.085

Herein, we report for the first time synthesis and electrochemical supercapacitance performance of 3-D hierarchical porous “Green” carbon derived from Pongamia pinnata seed oil extract cake and its activation using different amounts of KOH. Also, nanocomposites of multiwalled carbon nanotubes (MWCNT) with various weight percentages of Ni and Co were prepared by hydrothermal method. Physico-chemical properties of “Green” carbon and nanocomposites were analyzed by Powder X-ray Diffraction, Brunner Emmett Teller surface area, Scanning Electron Microscopy-Elemental Dispersive Spectrum, Transmission Electron Microscopy and Raman techniques. KOH activated carbon was found associated with combination of micropores & mesopores while the nanocomposite with mixture of spinel NiCo2O4 and Ni(OH)2. Porous carbon activated with 2:1::KOH:C (KC2) and the nanocomposite with 1:1 Ni & Co (NC1) exhibited excellent electrochemical performance in three electrode system. Further, fabricated asymmetric supercapacitor (AS) device Ni-Co-MWCNT (NC1)//KC2 exhibited specific capacitance (Cs) of 177 F/g as determined by cyclic voltammetry at 10 mV/s and retained 90% even at 3000th cycle in life cycle test conducted at high current density of 50 A/g. In order to evaluate its practical performance, the AS device was charged to 1.8 V at 5 A/g and used successfully to power a calculator for more than 1 h.
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•“Green” carbon was derived from Pongamia pinnata seed oil extract cake.•Surface properties of “Green” carbon were optimized using chemical activation.•Asymmetric supercapacitor (AS) using “Green” carbon & Ni-Co/MWCNTs was fabricated.•The AS device exhibited a high energy density of 44 Wh/kg.•The charged AS device could power a calculator for 1 h.