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Record ion speeds are achieved in organic conductors where local molecules can attract or repel ions from nanochannels that act as ion superhighways. Credit: Second Bay Studios
Researchers have significantly accelerated ion movement using nanotechnology, potentially improving technologies from battery charging to biosensing.
This breakthrough at Washington State University and Lawrence Berkeley National Laboratory involves creating a nanochannel lined with molecules that attract ions, allowing them to move over ten times faster than before. This development could revolutionize energy storage and help detect environmental pollutants or neurological activities.
Breaking Speed Records With Nanoscience
Researchers have shattered a speed record in nanoscience, unlocking potential advancements in areas like faster battery charging, biosensing, soft robotics, and neuromorphic computing.
At Washington State University and Lawrence Berkeley National Laboratory, scientists have discovered a method to increase ion movement by over tenfold in mixed organic ion-electronic conductors. These unique materials merge the ion signaling used by biological systems, such as the human body, with the electron signaling found in modern computers.
Innovating Ion Movement for Advanced Materials
Published on November 19 in Advanced Materials, this breakthrough relies on molecules that guide and concentrate ions into dedicated nanochannels, effectively creating a tiny “ion superhighway” that drastically accelerates their movement.
“Being able to control these signals that life uses all the time in a way that we’ve never been able to do is pretty powerful,” said Brian Collins, WSU physicist and senior author on the study. “This acceleration could also have benefits for energy storage, which could be a big impact.”
Impact on Technology and Energy Storage
These types of conductors hold a lot of potential because they allow movement of both ions and electrons at once, which is critical for battery charging and energy storage. They also power technologies that combine biological and electrical mechanisms, such as neuromorphic computing, which attempts to mimic thought patterns in the human brain and nervous system.
“Being able to control these signals that life uses all the time in a way that we’ve never been able to do is pretty powerful.”
Brian Collins, physicist, Washington State University
However, exactly how these conductors coordinate movement of both ions and electrons has not been well understood. As part of the investigations for this study, Collins and his colleagues observed that ions moved within the conductor relatively slowly. Because of their coordinated movement, the slow ion movement also slowed the electrical current.
Strategic Developments in Nanotechnology
“We found that the ions that were flowing all right in the conductor, but they had to go through this matrix, like a rat’s nest of pipelines for electrons to flow. That was slowing down the ions,” Collins said.
To work around this problem, the researchers created a straight nanometer-sized channel just for the ions. Then, they had to attract the ions to it. For that they turned to biology. All living cells, including those in the human body, use ion channels to move compounds in and out of cells, so Collins’ team used a similar mechanism found in cells: molecules that love or hate water.
Pioneering Faster Ion Transport
First, Collins’ team lined the channel with water-loving hydrophilic molecules which attracted the ions dissolved in water, also known as electrolyte. The ions then moved very quickly through channel — at speeds more than ten times faster than they would through water alone. The movement of ions represented a new world record for ion speed in any material to be documented.
Conversely, when the researchers lined the channel with hydrophobic, water-repelling, molecules, ions stayed away and were forced to travel through the slower “rat’s nest” instead.
Collins’ team found that chemical reactions could flip the molecules’ attractiveness to the electrolyte. This would open and close the ion superhighway, much the same way that biological systems control access through cell walls.
Future Directions and Applications
As part of their investigations, the team created a sensor that could quickly detect a chemical reaction near the channel because the reaction would open or close the ion superhighway creating an electrical pulse that a computer could read.
This detection ability on a nanoscale could help with sensing pollution in the environment, or neurons firing in the body and brain, which is one of many potential uses of the development, Collins said.
“The next step is really to learn all the fundamental mechanisms of how to control this ion movement and bring this new phenomenon to technology in a variety of ways,” he said.
Reference: “Local Chemical Enhancement and Gating of Organic Coordinated Ionic-Electronic Transport” by Tamanna Khan, Terry McAfee, Thomas J. Ferron, Awwad Alotaibi and Brian A. Collins, 19 November 2024, Advanced Materials.
DOI: 10.1002/adma.202406281
This study was supported by the National Science Foundation. In addition to Collins, researchers on this study include first author Tamanna Khan, co-authors Thomas Ferron and Awwad Alotaibi of WSU as well as Terry McAfee of Lawrence Berkeley National Laboratory.
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