No battery chemistry has come close to transforming the modern world like lithium-ion. It’s the reason your smartphone lasts a full day, why electric vehicles can travel hundreds of kilometers on a charge, and how engineers have managed to cram an impressive amount of power into devices smaller than a walnut. It’s the poster child of modern portable electronics, and it earned that place fair and square.
The secret sauce? Energy density. Lithium-ion batteries have an exceptional capacity for storing energy relative to their size and weight. This means designers and engineers get options. Need a long-lasting power source? Bulk it up. Need to save space? Shrink it down. Either way, you still get usable performance. Take Apple’s AirPods for example: these tiny wireless earbuds are not only cordless and barely noticeable in the ear, but they also run for hours on a single charge.
But let’s not get too romantic about it. For all its benefits, lithium-ion has a serious Achilles' heel—one that most people don’t think about until things go sideways.
When you pack that much energy into a tiny space, any damage to the battery turns it into a potential incendiary device. A puncture, overcharge, short circuit, or manufacturing defect can all cause a sudden discharge of energy. And that energy doesn’t quietly dissipate. It heats up. Fast. To the point of combustion.
And unfortunately, it doesn’t stop there. When a lithium-ion battery starts to fail, the chemistry inside doesn’t just produce heat. It also releases hydrogen gas. Highly flammable hydrogen gas. This means that a damaged cell can ignite from its own internal reactions—no spark required. In other words, lithium battery fires are self-starting and self-sustaining. Even after you think the flames are out, they can re-ignite spontaneously. That’s not just dangerous—it’s a nightmare scenario for firefighters, EV manufacturers, and anyone storing large volumes of cells.
Unlike traditional fires, these aren’t dependent on atmospheric oxygen. You can smother them, douse them, or even cool them down—but unless the internal reaction stops, they’ll light right back up. That’s what makes lithium-ion fires uniquely challenging. You’re not just dealing with flames. You’re dealing with a chemical reaction that doesn’t play by the normal rules of combustion.
Because of these risks, lithium-ion batteries are largely avoided in applications that require constant motion, bending, or deformation. You won't see them in flexible wearables or dynamic robotics unless the form factor is rigidly protected. There’s simply too much liability. All it takes is one cracked cell under strain, and you’ve got a literal hot mess.
Researchers from the University of California, Berkeley, have recently developed a new jelly-like lithium battery that can be used in soft robotics and wearable devices. The battery, which is made from a stretchable lithium-ion material, is able to withstand various forms of physical stress, including twisting, bending, cutting, and stabbing.
The new battery is made from a hydrogel electrolyte that is able to absorb and retain water. This allows for the battery to be flexible and soft, making it ideal for use in soft robotics and wearables. At the same time, the hydrogel electrolyte is able to maintain its electrical conductivity, allowing for the battery to store and release energy efficiently.
Typical hydrogen-based electrolytes are able to provide a high degree of flexibility, but they often struggle to provide high energy densities. This means that they are often unable to power devices for extended periods of time, making them unsuitable for use in soft robotics.
However, the new battery developed by the researchers is able to provide a significant improvement over traditional lithium-ion batteries, as well as hydrogen-based electrolytes. The use of a hydrogel electrolyte allows for the battery to maintain its flexibility and softness, while the use of a zwitterionic polymer helps to optimize the performance of the battery.
The researchers were also able to demonstrate the ability of the battery to self-heal after being damaged. This is particularly important for soft robotics and wearable devices, as they are often subject to various forms of physical stress. The ability of the battery to heal itself allows for it to continue functioning even after being damaged.
What the UC Berkeley team has pulled off here is nothing short of impressive. They’ve taken a notoriously rigid battery chemistry and made it soft, flexible, self-healing, and still somewhat energy-dense. That’s a big leap, and it opens doors that were previously welded shut for lithium-ion in flexible electronics.
However, while the prototype battery hits a respectable nominal voltage—around 3.3V, which is in the ballpark of standard 3.6V lithium-ion cells—it falls short where it really counts: cycle life. That’s the metric that tells us how many times a battery can be charged and discharged before it starts to degrade. In this case, the jelly battery just doesn’t hold up to the long-haul expectations of modern devices.
This means lower battery longevity and more frequent replacements—neither of which are ideal for commercial products or mission-critical applications. Imagine a wearable medical device that needs a new battery every few months, or a soft robot that loses performance after just a few charge cycles. Not exactly the kind of reliability engineers or users are aiming for.
That said, let’s not throw the baby out with the electrolyte. What the researchers have created isn’t vaporware—it’s a real, working prototype that proves this kind of chemistry can be done. That alone is a huge milestone. While it's not ready to disrupt the market today, it’s a highly practical step toward the next generation of flexible, safe, and adaptable power sources.
With some refinement—especially around cycle life and manufacturing scalability—this could become a go-to solution for devices where form and flexibility matter more than long-term endurance. And with the pace of innovation in material science, there's every reason to be optimistic that we’ll see this tech enter the mainstream within the next few years.
In short? It’s not a game-changer yet. But it’s absolutely on the roster.
