A team of researchers at Northwestern University has made a sustainable innovation by converting organic industrial waste products into an efficient storage agent. While there have been several works that aim to convert industrial waste into batteries, this new approach uses a waste molecule – triphenylphosphine oxide (TPPO).
Almost all devices, even cars, now rely on batteries that use metals like lithium and cobalt. Since these metals are sourced through intensive and invasive mining, shifting batteries away from metal-based solutions is critical to facilitating the green energy transition.
Organic industrial synthesis processes produce thousands of tons of waste annually, ultimately rendered useless, and must be disposed of carefully.
New research published in the Journal of the American Chemical Society uses a “one-pot” reaction to transform TPPO into a usable product with the potential to store energy. This finding could open new avenues for developing waste-derived organic redox flow batteries.
Redox flow batteries (RFBs) are rechargeable batteries where chemical energy is provided by two chemical components dissolved in liquids. Lithium or other solid-state batteries store energy in electrodes, unlike redox flow batteries. Though the redox flow batteries are not as efficient as the latter, they could offer a much better solution at a grid scale.
Lead author Christian Malapit says, “Battery research has traditionally been dominated by engineers and materials scientists. 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.”
Transforming CO2 into industrial fuels
Traditionally, organic molecules were found to be challenging to optimize for energy density and stability. Therefore, researchers were keen to look forward to a solution that would pack electrons tightly without losing storage capacity. The team found a strategy from a 1968 paper that described the electrochemistry of phosphine oxides.
To evaluate the molecule’s resilience as a potential storage agent, the team executed static electrochemical charge and discharge experiments. Even after 350 cycles of charge and discharge, the battery maintained remarkable health and capacity over time.
Malapit added, “This is the first instance of utilizing phosphine oxides – a functional group in organic chemistry – as the redox-active component in battery research. Traditionally, reduced phosphine oxides are highly unstable. Our molecular engineering approach addresses this instability, paving the way for their application in energy storage.”
Journal Reference
- Emily R. Mahoney, Maxime Boudjelel, Henry Shavel, Matthew D. Krzyaniak, Michael R. Wasielewski, and Christian A. Malapit. Triphenylphosphine Oxide-Derived Anolyte for Application in Nonaqueous Redox Flow Battery. Journal of the American Chemical Society. DOI: 10.1021/jacs.4c07750
