Researchers at Harvard have created a new organic molecule for flow batteries that promises to be a longer lasting and inexpensive alternative to lithium-ion batteries. This flow battery uses a new organic molecule that’s longer lasting and performs better than other flow batteries outlives and outperforms its predecessors (Photo via Harvard)


Harnessing energy from clean sources is important if we want to replace fossil fuels that are polluting the earth. The problem is we need a way to store the energy when the wind doesn’t blow, and the sun decides to quit. Organic flow batteries are a safe and inexpensive alternative to lithium-ion batteries when it comes to large-scale renewable energy. These batteries are ideal for energy storage, but they’re not exactly long lasting. Now, Harvard researchers have demonstrated a new organic molecule that outlives and outperforms other flow batteries making it the longest-lasting high-performance organic flow battery so far.


The molecule, nicknamed the Methuselah quinone after the longest-lived Biblical figure, has the ability to store and release energy tens of thousands of times over multi-year periods. The team created the new organic compound that stores electrical energy and lasts a long time before it decomposes. After studying the degradation processes of molecules used in other flow batteries, they created more stable molecules to address the problem.


This new molecule is a modified quinone, which is an abundant, naturally occurring molecule that’s important to biological processes, such as photosynthesis and cellar respiration. During testing, the Methuselah molecule had a fade rate of less than 0.01 percent per day and less than 0.001 per charge/discharge cycle. It can also store more energy in smaller, compact spaces. And since it operates in a weak alkaline electrolyte, it cuts the cost of the battery by using inexpensive containment materials and an inexpensive polymer membrane to separate positive and negative terminals.


Michael Aziz, who co-led the research with Thomas Dudley Cabot, says “In previous work, we had demonstrated chemistry with a long lifespan but low voltage, which leads to low energy storage per molecule, which leads to the high cost for a given amount of energy stored. Now, we have the first chemistry that has both long-term stability and comes in at more than one volt, which is commonly considered the threshold for commercial deployment. I believe it is the first organic-based flow battery that meets all of the technical criteria for practical implementation.”


While there’s still work to do on the flow batteries, the team hopes the new molecule will be a long-lasting, inexpensive alternative to costly vanadium batteries. “This important work represents a significant advance towards low cost, long duration flow batteries,” said Imre Gyuk, Director of DOE’s Office of Electricity storage program. “Such devices are needed to allow the electric grid to absorb increasing amounts of green but variable renewable generation.” Currently, they’re seeking out commercial partners to upscale the technology for industrial applications.


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