Swiss start-up shows bendable battery as thin as paper

Lorenz Keller

5/3/2026

Translation: machine translated

Pictures: Lorenz Keller

The Swiss start-up Btry impressed visitors at the Mobile World Congress in Barcelona with its ultra-small battery. It is as flexible and thin as paper, making it ideal for use in wearables or the Internet of Things.

Not only the big tech companies from Samsung to Google are present at the MWC in Barcelona, but also many start-ups. Among them is Btry from Dübendorf. The company, which was only founded in 2023, is showing the international audience a spectacular battery.

As thin as two sheets of paper

Compact energy sources are more in demand in the mobile industry than ever before. Smart rings, AR glasses and foldable gadgets - they all need a completely new type of battery. The battery needs to be small, compact and flexible. Just like the new development from Btry.

The Swiss start-up has a stamp-sized model on sale, for example, which is just 0.2 millimetres thick. That's as much as two sheets of paper laid on top of each other. The rechargeable battery, measuring 2.5 × 3 centimetres, has a voltage of 3 volts and a capacity of 5 mAh. A maximum current of 100 mA can be delivered.

The Btry model is a pure solid-state battery. It contains no liquid and can even be cut and still work. The battery is therefore robust, bendable and can be used in a temperature range from minus 40 to plus 150 degrees.

Btry also has a smaller variant with a lower capacity on sale. «The sizes are based on what is currently in demand on the market», explains CEO and co-founder Moritz Futscher. The product is ready to go, and the next step is to roll it out on a large scale with partners.

Ideal for tags and labels in logistics

Btry is not intended for expensive niche products, but for the mass market. The first applications for the paper rechargeable batteries are likely to be in the logistics sector. Stickers or labels are used there to track products along the entire supply chain. Until now, companies have primarily used tags with RFID (Radio-Frequency Identification). To read these, however, a terminal is required at each station. A tag with a rechargeable battery and Bluetooth, on the other hand, could be read with any smartphone. «Our battery is ideal for this application», says Futscher.

Btry is also well suited for wearables - which is why the Swiss are at the Mobile World Congress. «The flexible battery could, for example, power wristbands that record activities», says the founder. Flexible and bendable trackers would also be possible, for example a kind of airtag as a business card.

Makers of smart rings, among others, have shown interest. Until now, they have had to design a separate battery size for each ring size, which increases the cost. «I didn't realise that before. Btry can be adapted to different sizes much more easily», says Futscher.

So it may well be that the spin-off from ETH Zurich and the Swiss Federal Laboratories for Materials Science and Technology (Empa) will return to the Mobile World Congress in two or three years' time not just with a paper-thin battery, but with rings, trackers, AR glasses or fitness sensors that are powered by a Btry battery.

Lorenz Keller

Senior Editor

Lorenz.Keller@digitecgalaxus.ch

Gadgets are my passion - whether you need them for the home office, for the household, for sport and pleasure or for the smart home. Or, of course, for the big hobby next to the family, namely fishing.

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