Hyderabad: The batteries that power phones, cars, and other machines rely on metals like lithium and cobalt, sourced through intensive and invasive mining. However, this could soon change as scientists have found a new way to leverage industrial waste to store energy, potentially opening possibilities for a new kind of sustainable energy solution.
A team at Northwestern University has managed to use a waste molecule, triphenylphosphine oxide (TPPO), to power a redox flow battery.
Unlike lithium and other solid-state batteries which store energy in electrodes, redox flow batteries convert chemical energy into electrical energy through reversible oxidation and reduction reactions of working fluids. In other words, they use a chemical reaction to pump energy back and forth between electrolytes, where their energy is stored. Even though they are not as efficient at energy storage as conventional solutions, redox flow batteries are considered to be much better solutions at a grid scale.
Coming to TPPO, thousands of tons of this material are produced each year by organic industrial synthesis processes, but it is rendered useless and discarded post-production. The new research, published in the Journal of the American Chemical Society, a “one-pot” reaction allows chemists to turn this organic industrial waste product into a useful and powerful potential to store energy.
Emily Mahoney, a PhD candidate in the Malapit lab, highlighted that an organic molecule can achieve high energy density and high stability, approaching the performance of metal-based competitors. She noted that optimising both parameters together is usually challenging, which makes success with a waste-derived molecule particularly exciting.
The team searched for a strategy to achieve both energy density and stability that would allow electrons to pack tightly without losing storage capacity over time. They used a 1968 paper on the electrochemistry of phosphine oxides as a basis and tested the molecule's resilience through repeated charge and discharge cycles, similar to a battery's operation. They found that after 350 cycles, the battery retained its capacity remarkably well, with negligible loss over time.
Christian Malapit, lead author and an assistant professor in the department of chemistry at Northwestern’s Weinberg College of Arts and Sciences, pointed out that synthetic chemists can contribute to the battery research -- traditionally dominated by engineers and materials scientists -- by molecularly engineering an organic waste product into an energy-storing molecule. He said that their discovery showcases the potential of transforming waste compounds into valuable resources and offers a sustainable pathway for innovation in battery technology.
Malapit said this is the first time phosphine oxides, a chemical group, have been used in battery research. Normally, they are unstable, but the team's approach solved this problem, making them useful for energy storage. They hope other researchers will work with TPPO to further improve its potential.
