This is the first use of phosphine oxides as redox-active components in batteries, with molecular engineering enhancing their stability for energy storage.
Researchers at Northwestern University have developed a method for converting industrial waste into a key material needed to make batteries. Interesting Engineering writes about this.
A group of scientists used triphenylphosphine oxide (TPPO), a waste molecule, to power a redox flow battery.
Flow redox batteries use a chemical reaction to transfer energy between electrolytes that store it, unlike lithium and other solid-state batteries that store energy in electrodes. Metals like lithium and cobalt, which are mined through intensive and invasive mining, are essential for the batteries that power our phones, gadgets, and even cars.
Researchers emphasize that moving away from metal-based solutions will be critical to supporting the clean energy transition as more devices adopt battery-based energy storage technologies.
They believe that turning organic industrial waste into an effective storage agent for sustainable energy solutions could eventually be used on a much larger scale. This is the first time that a waste molecule, namely TPPO, has powered a redox battery.
Every year, industry generates thousands of tons of TPPO in processes such as organic synthesis, including the production of vitamins. It is usually considered useless and requires careful disposal.
Northwestern researchers have developed a “one-pot” reaction that allows chemists to convert TPPO into a valuable material with significant energy storage potential.
To address the energy density challenges in flow redox batteries, researchers have explored the use of nonaqueous systems and molecular engineering to create more advanced redox materials.
The study focused on phosphine oxides, specifically cyclic triphenylphosphine oxide (CPO), which has a very negative potential (-2.4 V vs. Fc/Fc+). CPO is produced from TPPO. Its unique structure, achieved through cyclization, enhances stability.
By studying how KPO decomposes under different conditions, the scientists developed a mixture of solvents. The scientists then conducted static electrochemical charge and discharge studies that mimic battery charging, use, and recharging to assess the molecule's reliability as a potential energy storage device. The battery remained remarkably functional after 350 cycles, with only a slight loss of capacity over time.