RMIT study finds lithium alternative

RECYCLABLE mobile phone batteries are a step closer due to a rust-busting invention.

Mobile phone batteries with a lifetime up to three times longer than today’s technology could be a reality, thanks to an innovation led by engineers at RMIT University.

The team at RMIT are working with a nanomaterial called MXene, a class of materials they say promises to be an exciting alternative to lithium for batteries in the future.

Rather than disposing of batteries after two or three years, we could have recyclable batteries that last for up to nine years, by using high-frequency sound waves to remove rust that inhibits battery performance, the team says.

Only 10 per cent of used handheld batteries, including for mobile phones, are collected for recycling in Australia, which is low by international standards. The remaining 90 per cent of batteries go to landfill or are disposed of incorrectly, which causes considerable damage to the environment.

The high cost of recycling lithium and other materials from batteries is a major barrier to these items being reused, but the team’s innovation could help to address this challenge.

Leslie Yeo, Distinguished Professor of chemical engineering and lead senior researcher, said MXene was similar to graphene with high electrical conductivity.

“Unlike graphene, MXenes are highly tailorable and open up a whole range of possible technological applications in the future,” Mr Yeo said.

The big challenge with using MXene was that it rusted easily, thereby inhibiting electrical conductivity and rendering it unusable.

“To overcome this challenge, we discovered that sound waves at a certain frequency remove rust from MXene, restoring it to close to its original state,” Mr Yeo said.

The team’s innovation could one day help to revitalise MXene batteries every few years, extending their lifetime up to three times.

“The ability to prolong the shelf life of MXene is critical to ensuring its potential to be used for commercially viable electronic parts,” Mr Yeo said.

Associate Professor, Amgad Rezk, one of the lead senior researchers, said the ability to quickly restore oxidised materials to an almost pristine state represented a gamechanger in terms of the circular economy.

“Materials used in electronics, including batteries, generally suffer deterioration after two or three years of use due to rust forming,” Mr Rezk said.

While the innovation is promising, the team needs to work with industry to integrate its acoustics device into existing manufacturing systems and processes.

The team is also exploring the use of their invention to remove oxide layers from other materials for applications in sensing and renewable energy.

“We are keen to collaborate with industry partners so that our method of rust removal can be scaled up,” Mr Yeo said.