How cool would it be if batteries, those rigid and bulky blocks that fill most of our devices, could adapt to any shape? This is not science fiction, but the concrete reality presented by researchers atLinköping University. Their 3D-printable, toothpaste-like, fluid battery heralds a new era in electronics.
It is estimated that within ten years we will have over a trillion connected devices: from classic smartphones and smart watches to wearable medical devices such as insulin pumps, pacemakers e sensors of health monitoring. And that's without counting the soft robotics, e-textile and neural implants. For all these gadgets, a fluid battery that can take any shape is not just convenient: it’s necessary. Energy rigidity, we know, has always been the invisible limit of technological design.
An electric “pasta” that makes the difference
"The consistency is a bit like toothpaste. The material can, for example, be used in a 3D printer to shape the battery as desired. This opens up a new type of technology," he explains. Aiman Rahmanudin, assistant professor at theLinköping University. There is something poetic in this description: energy that becomes fluid, that adapts rather than imposes its own form.
Batteries are currently the largest component of all electronic devices. Today they are solid and rather bulky. The problem has always been the same: the greater the battery capacity, the thicker the electrodes must be and therefore the greater the rigidity. A vicious circle that seemed impossible to break, until now.
But with a soft, adaptable battery, there are no design limitations. It can be integrated into electronics in a completely different way and adapted to the user. I am not exaggerating when I say that it could radically change how we interact with everyday technology.
Fluid Battery: Sustainability and Flexibility Together
Previous attempts to make soft, stretchy batteries have relied on different types of mechanical functions, such as rubber composites that can be stretched or connections that slide over each other. But these solutions didn’t address the heart of the problem: More active material means thicker electrodes and therefore greater stiffness.
“Here we’ve solved that problem, and we’re the first to show that capacitance is independent of stiffness,” Rahmanudin says.
Fluid electrodes have been tested in the past, but without much success. At that time, liquid metals such as gallium were used, but gallium can only function as an anode and risks solidifying during charging and discharging, losing its fluid nature. In addition, many of the previously made stretch batteries used rare earth materials with a large environmental impact during extraction and processing.
The future of flexible batteries
The researchers instead based their soft battery on conductive plastics (conjugated polymers) and lignin, a by-product of paper production. The battery can be recharged and discharged over 500 times while maintaining its performance. It can also be extended to double the length and work just as well.
“Because the materials in the battery are conjugated polymers and lignin, the raw materials are abundant. By reusing a by-product like lignin into a high-value commodity like battery material, we contribute to a more circular model. So it’s a sustainable alternative,” he explains. Mohsen Mohammadi, a postdoctoral researcher at LOE and one of the lead authors of the paper published Science Advances.
The fluid battery is still in the experimental stage; it currently provides 0,9 volts, but researchers are already working to increase this voltage using different chemical compounds such as zinc or manganese, two metals common in the Earth's crust.
I can't wait to slather some of this on myself somewhere.
