Using soundwaves to extend battery life

Mobile phone batteries with longer lifetimes could be a reality thanks to an innovation led by engineers at RMIT University. The team of engineers believes that the innovation could help develop recyclable batteries that last for up to nine years, by using high-frequency soundwaves to remove rust that inhibits battery performance. The high cost of recycling lithium and other materials from batteries is a barrier to these items being reused; however, the team’s innovation could help address this challenge.

The team is working with a nanomaterial called MXene, a class of materials that could be an alternative to lithium for batteries in the future. Leslie Yeo, Distinguished Professor of Chemical Engineering and lead senior research, said MXene is similar to graphene with high electrical conductivity. According to Yeo, MXenes are highly tailorable and open up a range of possible technological applications in the future. The big challenge with using MXene is that it rusts easily, thereby inhibiting electrical conductivity and rendering it unusable. “To overcome this challenge, we discovered that soundwaves at a certain frequency remove rust from MXene, restoring it to close to its original state,” Yeo said.

The innovation could help to revitalise MXene batteries every few years, extending their lifetime by 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,” Yeo said.

The research is published in Nature Communications.

Co-lead author Hossein Alijani said the greatest challenge with using MXene is the rust that forms on its surface in a humid environment or when suspended in watery solutions. “Surface oxide, which is rust, is difficult to remove especially on this material, which is much, much thinner than a human hair. Current methods used to reduce oxidation rely on the chemical coating of the material, which limits the use of the MXene in its native form. In this work, we show that exposing an oxidised MXene film to high-frequency vibrations for just a minute removes the rust on the film. This simple procedure allows its electrical and electrochemical performance to be recovered,” Alijani said.

The researchers’ work to remove rust from MXene opens the door for the nanomaterial to be used in a range of applications in energy storage, sensors, wireless transmission and environmental remediation. Associate Professor Amgad Rezk, one of the lead senior researchers, said the ability to restore oxidised materials to an almost pristine state represents a game changer, 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. With our method, we can potentially extend the lifetime of battery components by up to three times,” Rezk said.

The researchers will work with industry to integrate its acoustics device into existing manufacturing systems and processes. The team is also exploring the use of the innovation 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,” Yeo said.

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