New battery design better storage for renewable energy grid

Scientists have recently found a solution to store renewable energy even when the sun is not shining or the wind is not blowing.

Previously, scientists have proposed the solution is the giant battery block for the grid, to store electricity in liquid electrolyte containers. But so far, no cost-effective battery has been found, able to reliably power thousands of homes over a 10 to 20-year lifecycle.

A sample of AquaPIMs.

Now, a membrane technology developed by researchers at the Lawrence Berkeley National Laboratory (Berkeley Lab) of the US Department of Energy can offer a solution to this problem.

According to a report in Joule magazine, researchers have developed a flexible but affordable battery membrane from a polymer called AquaPIMs . This polymer makes grid batteries last a long time and at a low cost can only be based on readily available materials like zinc, iron and water.

The team has also developed a simple model that shows how different membranes affect battery life, expected to increase early research and development for the technologies. battery flow, especially in finding suitable membranes for different battery chemicals.

" The AquaPIM membrane technology is quickly accessible," said Brett Helms, principal researcher at the Center for Energy Storage Research (JCESR) and a scientist at Berkeley Lab. a market for flow-based batteries that use water-based chemicals at a low cost.Using our technology and accompanying experimental models for battery performance and life, researchers Another can quickly assess the readiness of each component to be inserted into the battery, from the diaphragm to the storage-charging material.This will save time and resources for researchers and developers. product".

According to Helms, fluorinated polymer films are quite expensive, they can account for 15% to 20% of the cost of the battery, making the consumption cost up to 300 USD / kWh. Miranda Baran, a graduate student in Helms' research group, said one way to reduce battery costs is to completely eliminate the fluorinated polymer film and suggest an alternative to a cheaper but High efficiency like AquaPIMs.

Berkeley Lab scientists have developed an affordable flow membrane for the grid from a new polymer called AquaPIM.

Through initial experiments, the researchers knew that the membranes were modified with a strange chemical called "amidoxime" that allowed ions to quickly move between the anode and the cathode.

Later, while evaluating the performance and compatibility of the AquaPIM membrane with various mesh battery chemicals, the researchers discovered that the AquaPIM membrane made the alkaline batteries significantly stable.

In addition, they discovered that the AquaPIM prototypes retained the integrity of the storage-loading materials in the cathode as well as the anode. When the researchers described the membranes at Berkeley Lab's Advanced Light Source (ALS) research facility, the researchers found that these traits are common on AquaPIM variants.

Ms. Baran and her collaborators then checked to see how the AquaPIM membrane would work with the alkaline water electrolyte. In this experiment, they found that under alkaline conditions, amidoxides combined a stable polymer, a surprising result considering that organic materials are often unstable at high pH.

Such stability has prevented the holes of the AquaPIM membrane to collapse, thus allowing them to maintain their electrical conductivity without sacrificing performance over time, while the holes of the commercial fluoro-polymer membrane collapse. predicting, detrimental to its ion transmission properties, Mr. Helms explained.

Diagram of a flow battery with ion-selective AquaPIM membrane (beige).Scientists at Berkeley Lab have discovered that such a model can predict the life and efficiency of flow batteries for the grid without having to fabricate the entire device.

While evaluating the performance and compatibility of AquaPIM membranes with various grid battery chemicals, the researchers developed a model that ties the battery performance to the performance of different membranes. This model can predict battery life and efficiency without having to make an entire device. They also point out that similar models can be applied to other battery chemicals and their membranes.

"Normally, you will have to wait weeks if not months to know how long the battery will last after assembling the entire cell. By using a simple and fast diaphragm, you can cut it down. hours or days left, " Mr. Helms said.

The researchers plan the next application of the AquaPIM film on a wider range of water-flow battery chemicals, from metals and inorganic substances to organic matter and polymers. They also predict that the membranes are compatible with other types of alkaline zinc batteries, including batteries that use oxygen, manganese oxide or organic metal frames as cathodes.

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