Mushroom skin could be made into biodegradable computer chips

Using mushroom skin as a base for computer chips and batteries could be a sustainable alternative that reduces the environmental impact of the technology.

As part of the process of manufacturing computer chips, their electronic circuits, made of conducting metals, need to sit in an insulating and cooling base called a substrate. This is often fabricated with non-recyclable plastic polymers, which are thrown away at the end of a chip’s life, contributing to the 50 million tonnes of electronic waste that is produced each year.

A team of researchers at Johannes Kepler University in Linz, Austria, has come up with a biodegradable alternative to these polymers, made from the skin of a certain type of mushroom. 

The mushroom used for this research was Ganoderma lucidum, which grows on dead hardwood trees. The scientists noted that the mushroom grows a skin to cover its mycelium – its root-like part – and protect it from other fungi and bacteria.

When extracted and dried out, the scientists found the skin to be a good insulator, as it was able to withstand temperatures of more than 200°C (390°F) and had a thickness similar to that of a sheet of paper. 

If kept away from moisture and UV light, the skin could probably last for hundreds of years, the researchers said, longer than the life of an electronic device. Moreover, it can also decompose in soil in around two weeks, making it easily recyclable.

“The substrate itself is the most difficult to recycle,” said Martin Kaltenbrunner at Johannes Kepler University. “It’s also the largest part of the electronics and has the lowest value, so if you have certain chips on it that actually have a high value, you might want to recycle them.”

The team developed a means for depositing metal electronic circuitry components onto the skin using physical vapour deposition, which was followed up with an ablated laser.

Testing of the result showed that the skin worked nearly as well as the traditional plastic substrates and that it could withstand being bent repeatedly. After 2,000 bends, the team found no breakage in the material. 

Kaltenbrunner and his team have constructed metal circuits on top of the mycelium skin and shown that they conduct almost as well as they do on standard plastic polymers. In addition to semiconductors, the team also hypothesised that the mushroom skin could also be used to produce certain types of batteries for low-power devices such as Bluetooth sensors or radio tags.  

“The prototypes produced are impressive and the results are groundbreaking,” said Andrew Adamatzky at the University of the West of England in Bristol, UK.

Since the shortage began in 2020, the economic losses caused by the lack of semiconductors can be measured in billions of dollars.

Over the past two years, the shortage of chips has forced Ford, Jaguar Land Rover, Volkswagen, General Motors, Nissan, Daimler, BMW, Renault and Toyota to shut factories, scale back production and exclude high-end features such as integrated satellite navigation systems, which rely on sophisticated semiconductor technology, from new vehicles.

The findings of the investigation were published in the journal Science Advances.