Knitting electronics with yarn batteries

1 min read

A team of researchers say they have developed a waterproof, flexible and rechargeable yarn zinc-ion battery, that maintains its charge capacity.

To enable progression of wearable electronics, a device that is deformable, durable, versatile and wearable must be created. And the team, led by Professor Chunyi Zhi at the City University of Hong Kong, believe one dimensional fibre, or yarn, shows promise. This Zhi explained is due to its size, flexibility and light weight.

Previous studies have had some success combining one-dimensional fibres with flexible Zn-MnO2 batteries, but many of these lose charge capacity and are not rechargeable, according to the Society.

To achieve its yarn battery, the group twisted carbon nanotube fibres into a yarn, then coated one piece of yarn with zinc to form an anode and another with magnesium oxide to form a cathode. These two pieces were then twisted like a double helix and coated with a polyacrylamide electrolyte and encased in silicone.

Upon testing, the group said the yarn zinc-ion battery was stable, had a high charge capacity and was rechargeable and waterproof. The material could also be knitted and stretched and cut into pieces, with each section able to power a watch.

In a proof-of-concept demonstration, the group explained that eight pieces of the cut yarn battery were woven into a long piece that could power a belt containing 100 LEDs and an electroluminescent panel.