Rice husk char as a potential electrode material for supercapacitors

Abstract

Rice husk char (RHC), a carbon-based material, was obtained by thermal decomposition of rice husk (RH) biological waste. Physicochemical properties of RHC were determined using XRD, FTIR, FESEM, TGA, N2 adsorption-desorption studies and contact angle mea­surement. A lab-scale supercapacitor (SC) was fabricated using as-prepared RHC and its super­capa­citive behaviour was investigated using techniques like CV, GCD and EIS studies. Each of RHC electrode showed a specific capacitance of 80.2 F g-1 at the constant charging/disharging current density of 0.05 A g-1. RHC exhibited 90 % retention of its initial capacitance even after 5000 GCD. The presence of amorphous SiO2 in RHC could contribute to the excellent wettability of RHC towards the water, enhancing its effective sur­face area by improving access of electrolyte ions into RHC. This remarkable super­capa­citi­ve performance of biological waste-derived RHC demonstrates its potential as a cost ef­fecttive and environ­mentally benign electrode material for aqueous electrolyte-based SCs.

Keywords

• Biochar
• carbon-SiO2 composite
• superhydrophilicity
• carbon cloth
• nanocomposite gel polymer electrolyte
• electric double layer capacitor (EDLC)