Synthesis and characterization of biodegradable gelatin based carbon nanotube composites for energy storage applications

Abstract

In this study, gelatin/Multi-Walled Carbon Nanotube (Gel/MWCNT), and gelatin/Single-Walled Carbon Nanotube (Gel/SWCNT) nanocomposites with different concentrations of CNTs were prepared by a facile solution casting process. Field Emission Scanning Electron Microscope (FESEM) images and Fourier Transform Infrared (FTIR) spectroscopy analysis showed an increased interaction between the CNTs and the polymer. The contact angle measurement showed the transition from the hydrophilic to the hydrophobic due to the addition of CNTs. Specific capacitance as high as 12.7 F/g at a current density of 0.3 µA/cm2 together with capacitance retention of 95% of the initial capacitance after completing 5000 charging-discharging cycles was obtained for the Gel/0.05% MWCNT sample. The Nyquist plot showed a decrease in charge-transfer resistance from 127 Ω to 75 Ω, and an increase in double-layer capacitance from 4 nF to 9 nF due to the incorporation of CNTs resulting in improved capacitive performance. Dielectric constant as high as 104 and a loss tangent of 0.91 were obtained for the Gel/SWCNT nanocomposite. The mechanism behind the improvement of the electrochemical performance was also elucidated. The biodegradability study showed that the nanocomposites fully degraded in few hours while emerging into the water. The Gel/CNT nanocomposites with improved electrochemical performance synthesized by a simple, low-cost process will pave the way to the production of sustainable, bio-friendly flexible energy storage devices.