Indian scientists have developed a low-cost and environment-friendly fabrication method for supercapacitor devices by utilizing industrial waste cotton as the electrode material and natural seawater-based electrolyte. The simple and sustainable supercapacitor developed shows excellent potential for practical implementation as energy storage in self-powered devices using solar cells.
The supercapacitor device was developed by the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), an autonomous organization of the Department of Science and Technology, Government of India.
In their study, ARCI scientists found that their natural seawater-based supercapacitor exhibited maximum capacitances at a current density of 1 ampere/gm (Ag-1). Besides, it showed excellent durability upon 10,000 charge-discharge cycles with 99% of capacitance retention and 99% of Coulombic efficiency (efficiency with which charge is transferred in a system facilitating an electrochemical reaction).
Fabrication and application
In their search for low-cost materials to make affordable supercapacitor, the ARCI scientists converted industrial waste cotton into highly porous carbon fibers by the activation process. They then utilised the porous carbon fibers to make high-performance supercapacitor electrodes.
They explored natural seawater as an environment-friendly, cost-effective and scalable substitute for the existing aqueous-based electrolytes.
The research team successfully demonstrated that the seawater-based supercapacitor could be combined with solar cells to enable low-cost, eco-friendly and efficient self-powered devices capable of energy storage. Thus, the integrated solar cell with supercapacitor can be used as an energy harvester storage device due to its long cycle life and maintenance-free power supply.
“The large-scale use of renewable energy requires the creation of matching capacity for inexpensive electrical energy storage. This study provides a solution for the fabrication of supercapacitors from such abundant materials as waste cotton and seawater! It is an excellent example of the creative science for the sustainable, green processes embedding principles of waste-to-wealth,” said Prof Ashutosh Sharma, Secretary, DST.