The world’s first fully functional quantum battery, proven as proof of concept, has been designed by CSIRO and its collaborators, the University of Melbourne and RMIT
You are late for an important appointment. When you are leaving the house, you realize that your cell phone is out of battery. Imagine you could charge it almost instantly by exploiting the strange rules of quantum physics. That’s the promise of quantum batteries.
In a study last week, in Light: Science & Applicationsa group of researchers from CSIRO (Commonwealth Scientific and Industrial Research Organization), in Australia, revealed the world’s first quantum battery prototypes.
You may have already heard about the peculiar quantum effects of superposition and entanglement, which allow generally very small objects to behave in very strange ways. They could also allow quantum computers to solve problems that conventional computers cannot.
A strange feature of the quantum world is what is called “collective effects”. They are what give quantum batteries their unique properties.
Under the right circumstances, quantum battery storage units do not act individually but behave collectively. This means that the Units charge faster together than if they were charging alone.
Let’s say your quantum battery has N storage units, and each unit takes one second to charge. The collective effects mean that if all units are charged at the same time, each unit will only take 1∕√N seconds to charge.
This means that, the bigger your quantum battery, the less time it takes to charge. If it doubles in size, it will only take a little more than half the time to load.
It’s as if each drive somehow knows that there are other drives around it, and their presence causes the drive to load faster.
That is radically different from the way conventional batteries workwhere larger batteries typically take longer to charge. That’s why it might take an hour to charge your cell phone, but your electric car needs it all night.
Build a quantum battery
The idea of a quantum battery was for a long time just a theoretical curiosity. But in 2018 this team set out to demonstrate that they could actually be built.
In 2022, a quantum battery prototype was built using an organic microcavity – a kind of small and complex multilayer “sandwich” of several different materials that traps light in a certain way.
For the first time, the exotic behavior in which larger quantum batteries actually take less time to charge was shown.
In fact, we were able to demonstrate that the charging time decreases as 1∕√N, where N was the number of molecules in our battery.
The more molecules included, the faster the battery charged — exactly as theory had predicted.
One thing the first prototype didn’t have was a way to extract energy from it. To do this, in the most recent study, extra layers were added to our device that converted the energy into an electrical current. This represents a huge step towards a practical quantum battery.
Progress still to be made
So why aren’t we seeing quantum batteries in stores?
A capacity of quantum batteries is still tinyand the time for which they maintain a charge is extremely short (a few nanoseconds). This means that the Quantum batteries are too small to power conventional devices like cell phonesat least for now.
However, quantum batteries could be perfect for powering quantum devices such as quantum computers. Quantum batteries could even be the solution that quantum computers need to work on larger scales and become practical.
Although there are no practical quantum batteries yet, scientists are working on ways to increase the size of the prototype and extend the time it can hold a charge.
The team wants to create a hybrid design that combines the exceptional charging speed of the quantum battery with the long storage time of the classical battery.
O Current progress is a testament to a century of theoretical work carried out by previous quantum scientists.
