Self-healing supercapacitors that make electricity with movement
doi:10.1038/nindia.2019.50 Published online 26 April 2019
Researchers have synthesised a composite system that can generate electricity by harnessing biomechanical energy such as finger tapping and heel pressing. The system, made by placing a supercapacitor between two layers of nanogenerators, can also store electricity and discharge it when needed.
Such a system will be useful for powering up portable electronic devices such as digital calculators and charging mobile phones in remote locations.
To integrate energy harvesting with storage in a single device, a research team, including scientists from the Indian Institute of Technology, Kharagpur, in India, fabricated the supercapacitor using a magnetic substance, a stainless steel fabric, an iron-oxide-decorated reduced graphene oxide sheet and a self-healing membrane made of hydrogel electrolyte.
The supercapacitor showed efficiency and stability even after an 8,000 cycles of charging and discharging. When mild hand pressure ripped a part of the supercapacitor, it healed on its own, quickly restoring its potential to light up light-emitting diodes (LEDs).
The researchers, led by Bhanu Bhusan Khatua, then embedded the supercapacitor between two layers of nanogenerators that was able to generate electricity from repeated elbow bending, shoe-sole pressing and sewing-machine imparting.
The combination of the supercapacitor and the nanogenerators produced an output voltage that lit up commercial red and green LEDs. It could also power up small electronic displays and wrist watches.
Since the composite system generates electricity from wasted biomechanical energy, it could be used to create a sustainable power source or a power back-up system for computers and modern vehicles, says lead author Anirban Maitra.
1. Maitra, A. et al. Triboelectric nanogenerator driven self-charging and self-healing flexible asymmetric supercapacitor power cell for direct power generation. ACS. Appl. Mater. Interfaces.11, 5022−5036 (2019)