'It's very counterintuitive': The quantum batteries that upend the rules of charging - BBC

Scientists have made the world's first quantum battery prototype and, unlike conventional batteries, it charges faster the larger it gets. Could these bizarre devices one day power quantum computing – or even your phone?

Everyone knows that the larger the battery, the longer it takes to charge – that's why it can take several hours to charge a laptop and typically all night to charge an electric vehicle.

That's the world we're familiar with, anyway. But in the world of the very small, different rules apply. Quantum mechanics (the science of matter at atomic and subatomic scales) "sort of flips [that] on its head", says James Quach, a quantum science researcher at Csiro, Australia's national science agency.

Quach is working to create a quantum battery that defies common sense by charging faster the bigger it gets. Just as some expect quantum computers to one day revolutionise computing, Quach argues that quantum batteries could be similarly disruptive.

In March 2026, his team made an important breakthrough when they unveiled what they say is the world's first working quantum battery prototype.

The field is still in its infancy, and quantum technology is inherently tricksy. But some scientists say these batteries could one day power quantum devices, while the strongest advocates insist they could even be used to charge everyday devices like phones.

Others, though, remain strongly sceptical about their real-world viability.

Conventional batteries rely on chemical reactions that send 10 billion billion electrons or more rushing through the device they're powering. It sounds impressive, but some now see the technology as outdated.

"Despite major technological improvements, modern batteries still rely on electrochemical processes first explored over two centuries ago," says Dario Ferraro, associate professor of physics at the University of Genova, Italy.

This has led some researchers to look towards quantum batteries – batteries that are powered by quantum effects, rather than chemical reactions.

The world of the very small is an overwhelmingly odd one. And quantum mechanics is no stranger to mind-bending concepts, from "entangled" particles that influence each other at great distances to time that flows backwards.

The research that laid the groundwork for quantum batteries was initially driven by curiosity about which laws of classical physics might be upended in the quantum world. A milestone paper in 2015 showed that quantum entanglement means quantum batteries might charge – and discharge – more efficiently than conventional ones.

"The key point is that quantum batteries are not about storing a great amount of energy, but about delivering it faster and with greater control," says Ferraro.

Quach has tested one way of harnessing these quantum effects to power a battery.

He uses an optical microcavity, an experimental set-up where two tiny mirrors are placed 100nm apart (a width about a thousand times thinner than a human hair). He fills the tiny space between the mirrors with organic dye molecules, then beams in a laser.

Using this method, the light and the molecules become strongly coupled, forming hybrid light-matter states, which enhances the system's ability to absorb and store energy – an effect known as superabsorption.

It's superabsorption that's responsible for the battery's most surprising property. In classical physics, molecules are little individualists – each acting on its own and absorbing energy at a rate independent of the molecules around it. But with quantum effects, they're a little more collectivist: they "act in unison and synergise", says Quach. "So that the rate at which you can absorb energy increases with the number of molecules there are."

It means that the more molecules there are (i.e. the bigger the battery) the faster it charges. Quach's prototype took femtoseconds (quadrillionths of a second) to charge, and stored the energy for nanoseconds, about six orders of magnitudes longer.

This feat was first demonstrated by Quach and his team in 2022. In March 2026, they added a new layer, managing to extract an electrical current from the prototype. At greater intensities, this current could potentially be used to charge devices.

Quach's optical microcavity method isn't the only way to make a quantum battery. Another approach, for example, uses superconductive materials – already widely used in quantum computing.

One big advantage of Quach's design, though, is that it works at room temperature. Superconductive designs only work at cryogenic temperatures starting below -150C (-238F). "This is fine for quantum computers, but not so useful to power your mobile phone," says Quach.

"If the goal is proving the quantum charging advantage as real physics… the optical microcavity route is the strongest bet," says Mauro Paternostro, a quantum physicist at Queen's University Belfast.

But in the long term, Paternostro believes that the superconductive design might have the edge for practical uses, because it is easier to extract energy from. "A microcavity gives you a beautiful ensemble demonstration, but poor control over getting the energy back out in a useful, directed form."

Quach's latest experiment represents a first tentative step towards a quantum battery that could one day be substituted for conventional ones. However, at present, the prototype battery can only hold a very small amount of energy – a few billion electron volts – for a matter of nanoseconds. To power conventional devices, it would need to store far more energy for far longer.

Quach says he has in fact already achieved this with a new design he's built, and is now working on a paper to publish the results. It uses "a hybrid structure", he says, involving quantum components to allow super-fast charging with classical layers added in to store the energy for longer.

He also plans to combine many microscopic quantum batteries together to increase their total capacity. "If we do those two things, then we're on our way to be able to power a conventional device," he says.

Still, other scientists remain sceptical, given quantum effects are notoriously fragile and are easily disrupted by observation or interference. "Interactions with the environment can quickly degrade [quantum] effects, limiting both performance and scalability," says Ferraro, which could offset part of the expected benefit of quantum batteries. Addressing this is "crucial to moving quantum batteries from theory to real-world applications", he adds.

Advancements in quantum batteries – if they are ever achieved – will likely impact quantum computing first. Quantum computers promise to one day execute tasks more rapidly than the fastest supercomputers, and technologists have warned they could threaten encryption globally.

Others, though, are more sceptical: a recent paper, for example, named quantum computers alongside fusion energy and brain-computer interfaces as being among the technologies perpetually described as "five years away".

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Quach, however, argues that he is likely to achieve the powering of quantum devices with quantum batteries in his lab within the next few years. If possible, this could reduce the amount of energy quantum computers consume, as well as making them faster and less error-prone, allowing them to be scaled up faster, he claims.

Quach is less certain about using them to power conventional devices. It should one day be viable, he says, noting the fact the battery is charged with a laser means it could potentially "charge electric vehicles on-the-go". This would avoid the need for drivers to stop to recharge altogether.

Ferraro, however, is sceptical that quantum batteries could ever become the norm outside of quantum applications. "In my view… quantum batteries are unlikely to replace conventional batteries in everyday applications such as mobile phones or electric vehicles," he says. "Their natural domain is the quantum scale."

The big unsolved problem right now, says Paternostro, is making use of the quantum charging advantage while also withdrawing the energy in a controlled, usable state. Whoever achieves this, he says, "will have made the real breakthrough".

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