Future smartphone batteries could charge within five minutes

Smartphones and laptops capable of charging in as little as five minutes are on the verge of becoming a reality, thanks to a new technique allowing researchers to observe the processes inside a lithium-ion battery as they happen.

Researchers from the University of Cambridge were able to pinpoint the processes that limit the speed at which batteries can recharge, in what they’re claiming represents an “important piece of the puzzle” in developing the next generation of batteries.

Smartphones, laptops and other electronic devices are typically powered by lithium-ion batteries, which contain carbon, metal oxide and a lithium salt electrolyte.

Energy is generated by the chemical reaction triggered by plugging in a charger, thanks to positively charged ions and electrons running in a circuit.

The study, published in Nature, will aid further research into why batteries fail, how to prevent it and how to develop new, faster-charging cells.

The team used an optical microscopy technique called interferometric scattering microscopy to observe the lithium ions moving inside batteries in real time, watching individual particles of lithium cobalt oxide (often referred to as LCO) charging and discharging by measuring the amount of scattered light.

They determined that the speed a battery was able to charge depended upon how quickly the lithium ions were able to pass through the particles of active material. Conversely, how quickly the battery discharged was dictated by how rapidly the ions were inserted at its edges.

Mastering control of the two mechanisms would allow lithium-ion batteries to charge significantly faster, said Dr Christoph Schnedermann, from Cambridge’s Cavendish Laboratory.

“Given that lithium-ion batteries have been in use for decades, you’d think we know everything there is to know about them, but that’s not the case,” he said.

“This technique lets us see just how fast it might be able to go through a charge-discharge cycle. What we’re really looking forward to is using the technique to study next-generation battery materials – we can use what we learned about LCO to develop new materials.”

While lithium-ion batteries boast relatively long lifecycles in comparison to other batteries, their risk of overheating and expensive production process mean they’re unsuitable for widespread use in electric cars and grid-scale storage for solar power, the study found.

“This lab-based technique we’ve developed offers a huge change in technology speed so that we can keep up with the fast-moving inner workings of a battery,” Dr Schnedermann added, pointing out that a better battery is one that can ideally both store a large amount of enegry and charge quickly.

“The fact that we can actually see these phase boundaries changing in real time was really surprising. This technique could be an important piece of the puzzle in the development of next-generation batteries.”