Sometimes it can feel a little depressing to wander the halls of the world's biggest tech show and find so little designed to tackle our planet's biggest problems. Every time I attend CESI keep my eyes peeled for technology that has the potential to make its mark on society in a deeper way, and I discovered a humdinger at this year's show. (Here are a few more from most eye-popping inventions.)
Read more: The official best of CES 2025 winners, presented by CNET Group
Singaporean startup Flint makes rechargeable paper batteries, which CNET picked as the winner of the Best of CES Sustainability Award on Thursday. They are completely flexible and can be shrunk down to the size of a coin battery or built into a smart watch band.
Flint's paper batteries share a structure with traditional lithium-ion batteries, but that's where the similarities end. Their key component is cellulose, which acts as a natural medium for the transfer of ions between the anode and cathode, a critical chemical exchange necessary for battery operation.
Mining and the manufacture of lithium-ion batteries are responsible for significant CO2 emissions, leaking toxic chemicals and depleting waterways, contributing to the wider climate crisis. As our needs for batteries grow rather than shrink, solutions like Flint's are critical to reducing the environmental impact of our technological obsession.
“Our supply chain is very abundant, and we're not looking for rare earths or toxic materials and scarce materials,” said Flint co-founder Carlo Charles. Some of them, like zinc and manganese, can even be found in your food and body, he added.
Disposing of traditional batteries also puts a strain on the environment, but paper batteries can biodegrade within six weeks. Charles tells me that at the team's office in Singapore, they compost their used batteries to feed the office plants.
Flint's batteries are biodegradable and can be used to supplement plants to feed plants.
Right now, the company is focused on making smaller batteries for smaller consumer electronics, but there's no reason they can't one day scale up. “We want to go even further and see how we can build our products into your smartphones,” said Charles. “Foldable smartphones could have foldable batteries… there's so much potential.”
Much further, the paper battery could be shrunk to fit inside the door of an electric door or the wing of an electric airplane. Because the batteries are so thin, they can be layered and also don't pose the same fire hazard as their lithium-ion predecessors.
In the week leading up to CES, Flint secured $2 million in funding that the company plans to use to build a pilot manufacturing facility in Singapore. Setting up a pilot in a country that doesn't have cobalt, lithium or other minerals traditionally used to make batteries will help prove the battery industry can be decentralized, Charles says.
The company already has plans to return to CES next year with an even bigger presence — though this year's booth was an impressive feat of sustainable engineering in its own right. The whole thing was made of cardboard that could be packed into one box.
With all of this, Flint has planted a flag at CES 2025. We're excited to see where the company's paper batteries go next.