Battery based on metallic lithium claimed to treble electric vehicle range

Using metallic lithium as the negative electrode in a battery has the potential to boost the battery’s performance by increasing the amount of charge it can store.

The team, based at the University of Waterloo in Ontario Province, has devised a method to get around two problems that have, until now, held back the development of metallic lithium batteries; corrosion of the electrode, which reduces the battery life, and development if microscopic whiskers of metal called dendrites caused by repeated charge-discharge cycles, which can lead to the risk of fires and explosions.

In a paper published in the journal Joule, the team explains that adding a phosphous sulphide (P₂S₅) to the battery’s electrolyte creates a thin film of a glassy protective compound, lithium sulphide (Li₂S₆) on the electrode which prevents both phenomena. This happens spontaneously inside an already-assembled cell, they add.

"We wanted a simple, scalable way to protect the lithium metal," said team leader Quanquan Pang, who completed his PhD at Waterloo and is now a postdoc at MIT. “With this solution, we just add the compound and it works by itself."