Greener sensors, circuit boards and other electronic devices are being developed by EU researchers to reduce unsustainably high levels of e-waste.

To develop eco-friendly electronics such as sensors and circuit boards, Dr. Valerio Beni is following the paper trail—literally.

An expert in green chemistry at Swedish research institute RISE, Beni has switched his focus to wood from pulp in a bid to make consumer electronic devices that have no carbon footprint and are easier to recycle.

In the woodwork

He and his colleagues discovered that producing pulp and turning it into paper for a new generation of electronics required burning too much energy for the effort to be as environmentally friendly as they had hoped.

"So we thought, why don't we take a step back and go to the initial material for making paper?" said Beni. "That is wood."

He leads a research project to explore ways to make consumer electronics with wood-based materials.

Called HyPELignum, the project runs for four years through September 2026 and brings together research institutes, a university and industry representatives from Austria, the Netherlands, Slovenia and Spain.

The life cycles of current electronics are unsustainable. In addition to the energy and raw materials needed for production, the gadgets result in mountains of waste once they get discarded.

In 2022, the world generated a record 62 billion metric tons of e-waste—or 7.8 kilograms per person—with Europe producing 17.6 billion metric tons, more than any other region, according to United Nations data.

That worldwide mountain has almost doubled from 34 billion metric tons in 2010 and is projected to increase to 82 billion metric tons by 2030.

In addition to growing fast, e-waste is complex to manage, according to the UN. In 2022, only about a fifth of global e-waste was recycled—although Europe fared better by recycling around 43%.

Better boards

Circuit boards are the main component of e-waste.

As much as 60% of the environmental impact of electronics is caused by a device's circuit board, according to Beni.

The boards are a layered matrix of materials—usually resins, plastics and copper, which are hard to recycle. They're etched to imprint metal circuits, onto which electronic components can be soldered.

As an alternative, the HyPELignum team is developing two types of wooden circuit board.

One is made of thin layers of wood, a bit like plywood. The other is constructed from cellulose fibers extracted from wood and wood waste.

"The idea is to try and replace some of the high carbon-intensive materials in electronics with low carbon-intensive material," Beni said.

The circuits are printed—rather than etched—onto the wooden boards using conductive metal inks developed by the project. These inks also contain cellulose and bio-based plastics produced from wood.

At the end of their life, the wooden boards should be easier to recycle than traditional circuit boards. It might even be possible to compost them.

New layers

A key challenge with recycling electronics is separating the components from the circuit boards.

To tackle this, the HyPELignum researchers are developing thermally and chemically degradable layers that can be placed between the wood and the printed circuits.

When these are destroyed at the end of a product's life, the circuits and electrical components fall off the wood. The wooden board and the mainly metal circuit and components can then be sent to different recycling streams.

Furthermore, the degradable layers are also derived from wood. The project has been producing them from lignin extracted from wood waste.

Such "green chemistry" emits much less carbon dioxide (CO₂) by featuring biogenic materials that can be renewed rather than fossil oil, according to Beni.

"Wood and biogenic materials are more or less zero in terms of CO₂ impact," he said. "They absorb CO₂ to grow and then they release the same CO₂ when used."