Electrochemical Energy Storage Potentials of Waste Biomass: Oil Palm Leaf- and Palm Kernel Shell-Derived Activated Carbons

• Main Authors: Salisu Nasir, Mohd Zobir Hussein, Zulkarnain Zainal, Nor Azah Yusof, Syazwan Afif Mohd Zobir
• Format: Article
• Language: English
• Published: MDPI AG 2018-12-01
• Series: Energies
• Subjects: oil palm wastes; chemical activation; activated carbon; electrochemical energy storage; supercapacitor; surface area
• Online Access: https://www.mdpi.com/1996-1073/11/12/3410

In this study, activated carbons (ACs) were produced from oil palm leaves (OPL) and palm kernel shells (PKS) using different concentrations (0%, 11%, and 33%) of H₃PO₄ as the activating agent. The Brunauer⁻Emmett⁻Teller (BET) results indicated that surface area decreases with the decreasing of the concentration of the H₃PO₄ in the following order: AC from oil palm leaves was (OPLAC-0% H₃PO₄) < (OPLAC-11% H₃PO₄) < (OPLAC-33% H₃PO₄), with the BET surface area values of 37, 760, and 780 m²/g, respectively. Similarly, the PKS-derived AC followed the same trend of (PKSAC-0% H₃PO₄) < (PKSAC-11% H₃PO₄) < (PKSAC-33% H₃PO₄), with the BET surface area values of 3, 52, and 1324 m²/g, respectively. Based on this finding, it was observed that H₃PO₄ had exhibited an influential role on enhancing the surface properties of the AC. On the contrary, it slightly decreased the graphitic trait of the AC by considering their I_G/I_D trends, which were generated from the Raman spectral analysis. The energy storage capacity of the AC was further tested using cyclic voltammetry. Three of the samples were found to have high capacitance values of 434 F g^−1, 162 F g^−1, and 147 F g^−1 at 5 mVs^−1. The first (434 F g^−1) is much higher than the specific capacitance value (343 F g^−1) of the only oil palm leaf-derived porous carbon nanoparticles ever reported in the literature.