Corn husk waste helps make supercapacitors
doi:10.1038/nindia.2020.123 Published online 14 August 2020
Researchers have chemically converted cork husk, an agricultural waste, into porous carbon material that could potentially be used as electrodes for making highly efficient supercapacitors1.
The researchers say it is possible to scale up the production of the carbon material from naturally abundant corn husk. Such carbon-based supercapacitors, they say, displayed better performance than the conventional supercapacitors.
Supercapacitors store and discharge energy more efficiently than conventional batteries. Their efficiency depends on the specific surface area and pore sizes of various carbon materials.
To make such a carbon material, scientists from the Indian Institute of Technology in Hyderabad, India, produced the porous carbon material from corn husk waste using a two-step chemical process. They then made a supercapacitor using the carbon material as electrodes and an organic electrolyte.
The researchers, led by Atul Kumar Deshpande, applied various voltages to the supercapacitor. This caused ions in the electrolyte solution to diffuse into the pores of the electrodes of opposite charge. The ions then accumulated at the interface between the electrodes and the electrolyte.
The supercapacitor retained 90 per cent of its efficiency in storing charges even after 5000 cycles of charging and discharging. This device, the researchers say, owes such stability and efficiency to the carbon material, which has a sheet-like structure, with micropores and nanopores.
Such pores, they add, help in the adsorption and desorption of the ions that store energy.
1. Rani, M. U. et al. Corn husk derived activated carbon with enhanced electrochemical performance for high-voltage supercapacitors. J. Power. Sourc. 471, 228387 (2020)