20, May 2019
Prelims level : Mains level :
GS 3 : Science & Technology – Awareness In The Fields Of It, Space, Computers, Robotics, Nano-Technology
Why in news?
Researchers at the Indian Institute of Technology (IIT) Bombay have fabricated a wearable supercapacitor that can store and deliver large amount of electrical energy, exceeding other similar devices
What is Capacitor and Supercapacitor?
- The capacitor is a component which has the ability or “capacity” to store energy in the form of an electrical charge producing a potential difference (Static Voltage) across its plates, much like a small rechargeable battery.
- A supercapacitor differs from the ordinary capacitor in that it has much higher capacity and energy density, while at the same time having a higher power density. These characteristics make it a convenient power source for devices that require high power and durability of the power unit.
- The wearable energy storage device can be stitched on to any fabric and can deliver power ranging from microwatt to milliwatt. The energy stored in the device can power GPS location-based transmitters or a 1.8 volt LED.
- Supercapacitor is integrated with a piezoelectric energy generator which will make it completely self-sustaining and when stitched to the fabric, the supercapacitor can be used for powering GPS location-based devices or a LED lamp or even charge small electronic devices.
- The electrode of the supercapacitor was fabricated by uniformly coating cotton yarn with carbon nanotubes (CNTs). The coating is done by dipping the yarn into carbon nanotube ink, where the CNTs are dispersed in water using a surfactant (detergent).
- The coating converts the electrical insulating yarn into a metallic conductor thereby behaving like an electrode. “The yarns coated with carbon nanotubes exhibited a finite electrical conductivity,”
- As the supercapacitor is targeting wearable and portable electronics hence researchers prepared a solid electrolyte film just 150 micrometre thick by mixing poly vinyl alcohol and potassium hydroxide in appropriate proportionsand stitched the solid electrolyte with CNT-coated yarn both vertically and horizontally. Capacitors were formed wherever the CNT wires criss-crossed each other and sandwiched the electrolyte.
- By increasing the number of stitches, and therefore, the number of capacitors, the amount of energy stored can be increased