Carbon fiber hewn structural batteries heralded as 'massless' solution for lighter devices

A Swedish startup could revolutionize building lighter laptops and other portable devices through its work with multipurpose materials. Specifically, its work with carbon fiber could lead to “massless” batteries where the material serves as energy storage and as part of the device’s outside case.

Tech startup Sinonus sprang from research at Chalmers University of Technology in Gothenburg, Sweden. A research team there has been working for years on developing carbon fiber that offers both the stiffness required for structural integrity and the electrochemical performance needed to store energy.

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

Of course, AAA batteries are a far cry from the ones you find in your laptop or smartphone. The challenge lies in engineering the carbon fiber crystals to have the energy density required to be effective. While Sinonus hasn’t published its current energy-density metrics, the 2021 prototype at Chalmers University only came in at 24 Watt-hours per kilogram (Wh/kg). By comparison, existing lithium-ion batteries in laptops typically have an energy density between 80 and 120 Wh/kg.

The recently appointed CEO at Sinonus, Markus Zetterström, acknowledged this challenge. However, he also pointed out that the material doubling as a structural integrity component helps justify the loss of electrical storage efficiency. “Storing electrical energy in carbon fiber may perhaps not become as efficient as traditional batteries, but since our carbon fiber solution also has a structural load-bearing capability, very large gains can be made at a system level,” he told New Atlas .

As Sinonus describes it, using “the mass that is already there” to store energy could serve to reduce the weight and volume of the device while still improving overall system performance. After all, if your laptop is smaller and lighter while still giving the same battery life, it hardly matters that the material storing the energy isn’t as efficient as a LiON battery pack.