Batteries are essential to modern life. They store energy collected by solar plants, power our smartphones, and lurk even in vehicles powered by fossil fuels. They’re so useful that we overlook their problems. Some batteries use potentially dangerous metals. Others have a pesky tendency to catch fire and explode when damaged.

Many companies have tried to design a battery that addresses these issues. Flint, a startup based in Singapore, is a new contender with a “paper battery.” I had the chance to pick it up and handle it for myself in January at CES, the annual consumer-electronics trade show. The battery, which in part uses cellulose, is lightweight and flexible. It can be a flat sheet that looks much like a thick piece of paper, or like a standard household AA or AAA battery. It doesn’t catch fire or leak if damaged and, contrary to what the term “paper” might lead you to think, it can be held up to a flame without igniting. It also claims to use fewer environmentally damaging metals than other batteries.

Carlo Charles, founder of Flint, says the company is rooted in the last two points. “When we started, it was a question of how we make batteries safer and more sustainable,” he says. “It wasn’t meant to be a company. It’s more of a passion project that snowballed into where we are today.”

Flint’s batteries started production in January 2026, and the company has partnered with Logitech to pilot its batteries in some devices.

What’s in a paper battery?

Flint isn’t the first company to produce a “paper battery.” IEEE Spectrum has covered several earlier attempts, including an “origami battery” powered by the respiration of microbes and a biofuel-based paper fuel cell from French startup BeFC.

However, Flint has less in common with these prior attempts than you might assume at a glance.

These prior examples were enzymatic fuel cells that convert an organic fuel source into energy. They used paper—or, to be precise, cellulose—as part of the fuel cell’s structure and mechanical design. Though they could be used like a battery, they weren’t batteries in a technical sense because they generated electricity from a fuel.

The raw materials and components seen here come together to form Flint’s battery cell, which sits in the center. Flint Labs

Flint’s technology is a true battery. Zinc is used as the anode and manganese dioxide is used as the cathode. This is a tried-and-true chemistry used by the inexpensive alkaline batteries that power hundreds of common household devices, from TV remotes to digital clocks.

How, then, does Flint’s battery use paper?

“We integrate cellulose across every battery component as much as we can,” says Charles, adding that Flint batteries can use cellulose as part of the casing, the cathode, the electrolyte, and the separator. “We remove PFAS from our chemistry, we remove cobalt, [and] we remove the solvent,” says Charles.

Charles was inspired by a paper from researchers at Singapore’s Nanyang Technological University that explored a “hydrogel reinforced cellulose paper” battery design. Charles connected with one of the researchers, Hong Jin Fan, who provided advice in Flint’s early days.

The use of cellulose in the battery is key to the company’s claim that it’s more environmentally friendly. Cellulose replaces metals and chemicals that are either dangerous to humans, produced through environmentally damaging processes, or both. Cobalt, for example, can cause cardiomyopathy, and cobalt mining can be extremely damaging to the local environment.

Flint batteries also lack corrosive materials found in alkaline batteries and the combustible materials in lithium-ion batteries. This improves their safety and physical flexibility. While not all Flint batteries are designed to be flexible, the battery can be produced in a thin format that I could bend between my thumb and index finger.

Flint claims high battery voltages and up to 1,000 charge cycles

The chemistry in Flint’s battery is similar to that of alkaline batteries, but the company hopes to rival lithium-ion in some applications, as well.

That’s a significant challenge. Lithium-ion is useful in part because it can deliver much higher voltages than an alkaline battery. An alkaline battery provides up to 1.5 volts, while lithium-ion can manage up to 4.2 volts.

Charles says Flint’s batteries can reach that mark. “Our batteries deliver high power, meaning up to 4.2 volts, and an energy density of 226 watt-hours per kilogram,” he says. The battery is rechargeable and can endure up to 1,000 charge cycles, also roughly comparable to lithium-ion, which can last 300 to 2,000 or more cycles, depending on the chemistry.

Flint’s manufacturing setup, which will process battery material at scale, uses a roll-to-roll process similar to that of a printing press. Flint Labs

Flint has not published a white paper on its design and is currently keeping the details of its battery design under wraps. A company spokesperson said Flint’s technology includes “proprietary tweaks across the cathode, electrolyte, anode, and separator.”

Though Flint makes big claims about its battery, Charles acknowledged that lithium-ion will be tough to rival and said the company isn’t ready to challenge lithium-ion in applications that push the limits on power density.

“We do not want to focus on electric vehicles, because we know they require even more life cycles and even higher power densities,” he says. Instead, Flint has its sights on lower-power devices commonly found in households, such as sensors, remotes, portable health care devices, and even smartphones. “I want to replace everything [with a battery] I can see around me in my house or workplace with a Flint battery.”

2026 is a crucial test for that vision.

The company is speaking with potential customers, such as Logitech, which sells peripherals for PCs and smartphones. Flint won Logitech’s 2025 Future Positive Challenge and has partnered with Logitech to pilot use of Flint AAA batteries.

If successful, this partnership would help Flint demonstrate that its technology can deliver on its goal to reduce the impact batteries have on the environment. “[Logitech ships] many millions of batteries each year in their products. Even reducing a few grams of carbon emissions per product can be a big impact for them,” says Charles.