A research team led by Lynden Archer, professor and dean of Cornell Engineering, has developed a lithium battery that can charge in as little as five minutes. This could help address anxiety associated with the charging time of electric vehicles (EVs) and increase their adoption.

In their bid to reduce emissions from transportation, countries worldwide are looking to electrify various modes of transport. Road-based transport such as cars, buses, and trucks have led this transformation, aiming to even ban the sale of fossil fuel-powered cars in the next decade.

With technological advances, the fastest commercial charger can charge up an EV in no less than 30 minutes. While this might be a major improvement over the eight-hour charge cycles of a typical home-based charger, it still needs to be improved for large-scale adoption of EVs. 

"If you can charge an EV battery in five minutes, you don't need to have a battery that's big enough for a 300-mile [480km] range," said Archer in a press release. "You can settle for less, which could reduce the cost of EVs, enabling wider adoption."

Change in approach

Archer's team has previously worked on the charging problem of lithium-ion batteries. However, the team's approach has focused on the movement of ions in electrolytes and their crystallisation at metal anodes. The team used its expertise in these processes to make safer anodes that offer long-term storage. 

To devise a faster-charging battery, the team took a new approach by focusing on the kinetics of the electrochemical reactions. They looked keenly at a concept called the Damköhler number, which measures the reaction rate and the rate at which material is transported to a reaction site.

The team specifically looked for materials with low Damköhler numbers, which have fast transport rates, and found that a soft metal named indium could be used. 

Batteries that charge in five minutes

Indium is commercially used as a low-temperature solder to make indium tin oxide, a coating material for solar panels and touch screens. The researchers found that the metal has a very low migration energy barrier, which can help set the ion diffusion rate. It also has a good exchange current density, which is the reduction rate of ions at the anode. A combination of both these factors results in fast charging and long-duration storage.

"The key innovation is we've discovered a design principle that allows metal ions at a battery anode to freely move around, find the right configuration and only then participate in the charge storage reaction," said Archer.

"The end result is that in every charging cycle, the electrode is in a stable morphological state. It is precisely what gives our new fast-charging batteries the ability to repeatedly charge and discharge over thousands of cycles." 

The researcher suggests that combining the technology with induction-based wireless chargers can help reduce the size of the battery packs needed on vehicles, thereby reducing costs as well.

There is also an obstacle to overcome, though. Indium is very heavy and may not be suitable for making battery packs. The team is now working on discovering other lightweight materials that could perform the same role as indium.

The research was published in the journal Joule recently.