Context: Recently, scientists at the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI) have developed a simple, low-cost, environment-friendly, and sustainable supercapacitor device.

• ARCI is an autonomous organization of the Department of Science and Technology, Government of India.

About Supercapacitor

• A supercapacitor is a high-capacity capacitor with a capacitance value much higher than other capacitors, but with lower voltage limits, that bridges the gap between electrolytic capacitors and rechargeable batteries.
• A capacitor is a device that stores electrical energy in an electric field.
• It typically stores 10 to 100 times more energy per unit volume or mass than electrolytic capacitors, and can accept and deliver charge much faster than batteries.
• The supercapacitor is a next-generation energy storage device that has received extensive research attention owing to advantages such as high power density, long durability, and ultrafast charging characteristic as compared to conventional capacitors and lithium-ion batteries (LIB).
• Among the four main components of a supercapacitor – electrode, electrolyte, separator, and the current collector, the first two are the pivotal components, which directly determine the electrochemical behaviour of the supercapacitors.
• The fabrication cost of electrode materials, as well as electrolytes, should be reduced because these two components account for a major portion of the device manufacturing cost.

Key findings of the study

• In search of a cost-effective material for making affordable supercapacitor devices, scientists at ARCI have converted industrial waste cotton into highly porous carbon fibres by activation process and then utilised the porous carbon fibres to make high-performance supercapacitor electrodes.
• The team also demonstrated the feasibility of using seawater as a natural electrolyte for the fabrication of aqueous-based supercapacitor devices, which shows great potential for practical implementation.

Benefit

• This supercapacitor showed great potential for practical implementation.
• It exhibited maximum capacitance, good durability and high efficiency.
• Capacitance is the ability of a system to store an electric charge.
• Efficiency denotes the charge transfer in a system facilitating an electrochemical reaction.
• When integrated with a solar cell, the supercapacitor will become a low cost, eco-friendly, efficient and self-powering device.
• It has a long life cycle and can be used as maintenance-free power supply.
• It can also overcome the drawbacks of the intermittent nature of the solar irradiation.

Road Ahead

• For the first time, natural seawater is explored as an environmentally friendly, cost-effective, scalable, and alternative aqueous electrolyte, which may replace the existing aqueous-based electrolytes for the economic fabrication of supercapacitor.
• The development is an excellent example of creative science for the sustainable, green processes embedding principles of waste-to-wealth.