Scientists Invented a Liquid-Like Battery That Can Basically Recharge Forever

Yahoo

15-04-2025

As the world continues to become ever more interconnected, wearables, implants, and other technologies need batteries that can stretch to fit a variety of form factors.
Scientists from Linköping University in Sweden developed a flexible battery—using liquid electrodes, conductive plastics, and lignin—that can stretch twice its length and maintain performance.
While the battery needs to increase its voltage to compete with lithium-ion competitors, the idea shows promise for a world full of flexible technologies.
On April 3, 1973, Motorola engineer Martin Cooper made the first cellphone call. Within 50 years, the number of cellphones—now empowered with all the wonders (and detriments) of the internet—has reached around 7.2 billion. This explosion of mobile technology wouldn't be possible without some serious battery advancements, and as the world rushes toward one trillion connected devices in the next decade, it'll take new innovations to power that future.
Although these batteries get increasingly more impressive over time—the first smartphone, IBM's Simon, had a not-so-stellar one-hour battery life—limitations remain, including that batteries make up the bulk of most electronics and they're famously inflexible. In fact, flex a lithium-ion battery too far and you may just have a flammable disaster on your hands.
But in a new study from Linköping University in Sweden, scientists think they might have developed a fluid solution for batteries' famous inflexibility. By converting solid electrodes to liquid, scientists at the Laboratory of Organic Electronics at Linköping University have successfully created a battery that can stretch double its length and maintain performance. The results of the study were published today in the journal Science Advances.
'The texture is a bit like toothpaste,' Aiman Rahmanudin, a co-author of the study, said in a press statement. 'The material can, for instance, be used in a 3D printer to shape the battery as you please. This opens up for a new type of technology.'
This is a good thing, as not all electronic applications come in easy, one-size-fits-all, candy-bar-shaped sizes. Wearable technologies, insulin pumps, hearing aids, pacemakers, and the developing world of fast robotics all need flexible batteries in some unconventional sizes for them to work. There's just one problem—capacity often coincides with rigidity. So, if you make something flexible, you inherently degrade a battery's core function: powering stuff.
To address this problem, the research team developed a flexible battery using liquid electrodes and a material made from conductive plastics and lignin—a byproduct of paper production. They found that the battery could be recharged and discharged over 500 times without losing performance, and could stretch to double its length. On top of all that, because it doesn't rely on rare earth materials, it's also an environmentally conscious battery.
'Since the materials in the battery are conjugated polymers and lignin, the raw materials are abundant,' Mohsen Mohammadi, a postdoctoral fellow and co-author of the study, said in a press statement. 'By repurposing a byproduct like lignin into a high value commodity such as a battery material we contribute to a more circular model. So, it's a sustainable alternative.'
Flexible? Check. Sustainable? Also check. So, what's the catch? Well, right now, the voltages in the battery can't quite compete with lithium-ion batteries. Battery voltages in a typical smartphone can tick upwards of four volts, but the researchers say their flexible creation hovers around 0.9 volts, so future research will look into ways to increase that voltage. To maintain the battery's sustainable bonafides, the scientists say they're considering chemical compounds using zinc or manganese—two of the most abundant metals found on Earth.
Fifty years ago, a smartphone battery could barely last longer than an episode of The White Lotus. Now, they can hold a charge for days at a time. In the next half century, who knows where flexible batteries might take us.
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