- Researchers develop a new organic molecule that offers the high-performance, longest-lasting organic flow battery so far.
- It has tens of thousands of charge-discharge cycles with a degradation rate of 3% per year.
Fossil Fuels are polluting our environment at an extremely fast rate. If everything goes at the pace, we won’t be able sustain human civilization in the future. That’s the reason researchers are trying very hard to harness the clean energy sources.
Wind and solar energy can provide all the essential energy we are going to need in the future. However, we will need a storage system that can supply power uninterruptedly when the wind isn’t blowing an the sun isn’t shining.
Conventional enclosed batteries are common, but they are expensive can’t store enough energy for longer discharge durations. Redox-flow battery, on the other hand, supports longer-duration discharge because energy-stacking modules are held in liquid state in external tanks, which are isolated from the power generation stack.
Therefore, power and energy rating can be influenced independently, and energy to power ratios (discharge cycles) of days can be obtained at the rated power. These organic flow batteries are relatively cheaper and safer than vanadium flow and lithium ion batteries for large-scale renewable energy storage systems.
Now, a research team at Harvard University has developed a new organic molecule named Methuselah quinone, that offers the high-performance, longest-lasting organic flow battery so far. The molecule is capable of storing and releasing energy tens of thousands of times over several years.
The Methuselah Molecule
The findings are built on previous research in which the team demonstrated a technique that leads to low energy storage per molecule. Now they have improved the chemistry to achieve long-term stability at more than 1 volt, which is a threshold for industrial deployment.
The Methuselah molecule is an improved quinone (a class of organic compounds), an abundance of naturally occurring molecule integral to biological process such as cellular respiration and photosynthesis.
Researchers carefully examined the degradation process of quinone compounds in organic flow batteries and made some improvements to extend its life. They claim it’s the first organic flow battery that can be practically implemented and used for real-world applications.
Flow battery using Methuselah molecule | Image credit: Eliza Grinnell
They carried out numerous experiments and found the Methuselah molecule has a fade rate of less than 0.001% per charge-discharge cycle and less than 0.01% per day. This equates to less than 3% degradation in one year, and operational for tens of thousands of cycles.
Since the molecule is highly soluble, it can hold more energy in a compact space. It works in a weak alkaline electrolyte, and thus it can be integrated with less expensive polymer membrane (to isolate negative and positive terminals) and less expensive containment materials.
All of these new methodologies make organic storage systems cost-effective for long cycle and calendar life. In the future, we will need these types of devices to enable the electric grid to absorb inconsistent renewable generation.