Scientists transform waste into batteries that could power grid

Scientists have discovered a way to turn previously useless industrial waste into a vital material used in batteries.

The waste molecule, triphenylphosphine oxide (TPPO), is produced in the manufacture of products like vitamin tablets. A new process discovered by scientists at Northwestern University in the US turns it into a useful agent for storing energy that could replace rare metals in some situations.

Unlike more common lithium batteries, which store energy in electrodes, the redox flow batteries that can be created with this new process use a chemical reaction to pump energy back and forth between electrolytes where their energy is stored.

They aren’t quite as efficient at energy storage as other forms of batteries and are too big and bulky to be used in cars or smartphones. They are, however, thought to be a much better solution for energy storage on the scale of an electricity grid. That includes storing energy from renewables like wind and solar to help smooth out troughs and peaks in supply.

“Not only can an organic molecule be used, but it can also achieve high-energy density – getting closer to its metal-based competitors – along with high stability,” says Emily Mahoney, a PhD candidate and the paper’s first author.

“These two parameters are traditionally challenging to optimise together, so being able to show this for a molecule that is waste-derived is particularly exciting.”

Turning industrial trash into treasure

As requirements for batteries continue to grow, so does the requirement for metals like lithium and cobalt used to create them.

These metals are often sourced through intensive and invasive mining. There is also a limited supply of them and researchers say that as more and more products depend on batteries, a shift away from these metal-based solutions to more sustainable options will be needed.

“Battery research has traditionally been dominated by engineers and materials scientists,” says Northwestern chemist and lead author Christian Malapit.

“Synthetic chemists can contribute to the field by molecularly engineering an organic waste product into an energy-storing molecule. Our discovery showcases the potential of transforming waste compounds into valuable resources, offering a sustainable pathway for innovation in battery technology.”

Tonnes of TPPO are produced each year but it is currently rendered useless and must be carefully disposed of. More research is needed into the potential to turn this trash into green treasure but scientists are hopeful that it could be used to store renewable energy in the future.