Deakin scientists develop better performing lithium batteries

Photo: Deakin University

Deakin University scientists have created a first-of-its-kind lithium metal battery prototype using specially-designed electrolytes.

“Over the past 30 years, researchers at Deakin and Monash University have been working on a new class of electrolyte material called an ionic liquid, which is a salt that takes on a liquid form at room temperature,” director of the University’s Battery Technology Research and Innovation Hub (BatTRI-Hub), Professor Patrick Howlett, said.

“Ionic liquids are non-volatile and resistant to catching fire, meaning that unlike the electrolytes currently used in lithium-ion cells used by, for example Samsung and Tesla, they won’t explode. Not only that, but they actually perform better when they heat up, so there’s no need for expensive and cumbersome cooling systems to stop the batteries from overheating.”

The breakthrough represents a viable alternative to the popular rechargeable lithium-ion batteries currently in use in portable electronics and electric vehicles; and is the culmination of more than 10 years of work at Deakin by IFM electromaterials experts led by Professors Maria Forsyth and Howlett.

Aside from allowing for good safety, high temperature stability, and high voltage stability for increased energy storage capacity, the aspect of ionic liquid electrolytes that has most energised the team’s research efforts is their outstanding ability to cycle energy-dense lithium metal electrodes.

“By changing the materials that go into the batteries, we can change a number of key features,” IFM research fellow, Dr Robert Kerr, who has worked on translating these materials into real devices, said.

“For example, if we change the electrodes to include lithium metal we can increase the storage capacity for up to 50 per cent longer run-times. When we change the electrolyte, it can give a higher discharge rate or allow the battery to operate at much higher temperatures – but the electrolyte must be compatible when in contact with the reactive lithium metal electrode.

“The use of lithium metal electrodes in lithium metal batteries isn’t common in the battery industry, so there’s little known about the best way to manufacture these cells at practical levels for demonstration,” Kerr said.

“After years of painstaking attention to manufacturing processes and details, the team has achieved a benchmark level that’s sure to make everyone in the industry sit up and take notice. While this is just a stepping stone on the way to 1.7Ah cells, which are soon to be in production, this is an important milestone in the battery world for the demonstration of a new technology.”