Energy & Green Tech

The team discovers significant storage capacity in water-based batteries.

The storage capacity of metal-free, water-based battery electrodes differs by 1,000%, according to researchers at Texas A&M University.

These batteries are distinct from cobalt-containing lithium-ion batteries. The group’s desire to study metal-free batteries stems from the need to have better control over the domestic supply chain because cobalt and lithium are imported. Battery fires would not occur thanks to this safer chemistry.

In Nature Materials, chemical engineering professor Dr. Jodie Lutkenhaus and chemistry assistant professor Dr. Daniel Tabor have published their research on lithium-free batteries.

Because it is water-based, Lutkenhaus claimed that battery fires would no longer occur. The cost of lithium-ion batteries will significantly increase if future shortages of materials are anticipated. If we have this alternative battery, we can use this chemistry, where the supply is much more stable because we can manufacture them here in the United States and the materials to make them are here.”.

“If material shortages are predicted in the future, the price of lithium-ion batteries would skyrocket. If we have this alternate battery, we can switch to this chemistry, where the supply is considerably more stable since we can produce them here in the US and the ingredients to build them are available.”

Chemical engineering professor Dr. Jodie Lutkenhaus 

A cathode, an electrolyte, and an anode are what Lutkenhaus described as being present in aqueous batteries. Energy-storing polymers serve as the cathodes and anodes, while water and organic salts make up the electrolyte. Through its interactions with the electrode, the electrolyte plays a crucial role in ion conduction and energy storage.

She explained that if an electrode swells excessively while cycling, it won’t be able to conduct electrons very well, which will result in a complete loss of performance. “I think that the electrolyte choice affects energy storage capacity by a factor of 1,000 because of swelling effects.”.

According to their article, the high discharge voltage and quick redox kinetics of redox-active, non-conjugated radical polymers (electrodes) make them promising candidates for metal-free aqueous batteries. Because electrons, ions, and water molecules are all being transferred at once, the reaction is complicated and challenging to understand.

The authors of the article explain that they used an electrochemical quartz crystal microbalance with dissipation monitoring over a range of timescales to examine aqueous electrolytes with varying chao- and kosmotropic characters in order to “demonstrate the nature of the redox reaction.”.

The experimental work was supplemented by computational simulation and analysis carried out by Tabor’s research team. The molecular-scale, microscopic picture of the structure and dynamics was revealed by the simulations.

To understand these materials, theory and experiment frequently collaborate closely. We actually charge up the electrode to multiple states of charge and see how the environment responds to this charging as one of the novel computational tasks we perform in this paper,” Tabor said.

By precisely measuring the amount of salt and water entering the battery while it is operating, researchers were able to macroscopically determine whether the cathode of the battery was performing better in the presence of particular types of salts.

He said, “We did that to explain what has been observed experimentally.” At this point, we would like to include future systems in our simulations. We needed evidence to support our theory about the forces behind this kind of water and solvent injection.

A step toward lithium-free batteries has been made possible by this new energy storage technology. We now have a clearer understanding of the molecular mechanisms underlying why some battery electrodes perform better than others, and this provides us with compelling data on how to move forward with material development,” Tabor said.

More information: Ting Ma et al, The role of the electrolyte in non-conjugated radical polymers for metal-free aqueous energy storage electrodes, Nature Materials (2023). DOI: 10.1038/s41563-023-01518-z

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