Structural hewn carbon fiber batteries, advertised as a “massless” solution for lighter devices

A Swedish start-up could revolutionize the construction of lighter laptops and other portable devices by working with multifunctional materials. In particular, his work with carbon fiber could lead to the creation of “massless” batteries, in which the material is used to store energy and forms part of the device’s outer casing.

The technology startup Sinonus was created as a result of research at Chalmers University of Technology in Gothenburg, Sweden. The research team there has been working for years to develop carbon fiber that provides both the stiffness required for structural integrity and the electrochemical properties needed for energy storage.

Chalmers University of Technology and venture capital firm Chalmers Ventures turned the project into a startup, and Sinonus is now working to commercialize carbon fibers that also act as electrodes. Sinonus has already developed a proof of concept by replacing AAA batteries with carbon electrode batteries in the lab.

Of course, AAA batteries are significantly different from those found in your laptop or smartphone. The challenge is to design the carbon fiber crystals to have the energy density necessary for their efficiency. Although Sinonus has not published its current energy density ratings, the 2021 prototype at Chalmers University only achieved 24 watt-hours per kilogram (Wh/kg). For comparison, existing lithium-ion batteries in laptops typically have an energy density of 80 to 120 Wh/kg.

Sinonus’ recently appointed CEO, Markus Zetterström, was aware of this challenge. However, he also noted that doubling the material as part of the structural integrity helps justify the loss of electrical energy storage efficiency. “Storing electricity in carbon fiber may not be as efficient as traditional batteries, but because our carbon fiber solution also has the ability to carry structural loads, very large benefits can be achieved at the system level,” New Atlas said.

As Sinonus describes it, using “mass that already exists” for energy storage could help reduce the mass and volume of the device while improving overall system performance. After all, if your laptop is smaller and lighter while still providing the same battery life, it doesn’t matter that the energy storage material isn’t as efficient as a LiON battery.