A new speed record has been achieved through innovative nanoscience, paving the way for transformative advancements in areas such as faster battery charging, cutting-edge biosensing, agile soft robotics, and revolutionary neuromorphic computing.
Researchers from Washington State University and Lawrence Berkeley National Laboratory have found a method to accelerate the movement of ions by over ten times in mixed organic ion-electronic conductors. These special conductors merge the benefits of ion signaling found in various biological systems, like the human body, with the electron signaling utilized by computers.
The innovation enhances ion mobility in these conductors by employing molecules that draw and concentrate ions into a distinct nanochannel, effectively creating a miniature “ion superhighway.”
“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 of the study. “This acceleration could also have benefits for energy storage, which could have a big impact.”
These kinds of conductors have significant potential because they facilitate the simultaneous movement of both ions and electrons, which is essential for battery charging and energy storage. They also drive technologies that integrate biological and electrical processes, such as neuromorphic computing, which seeks to replicate thought patterns found in the human brain and nervous system.
Nevertheless, the mechanisms by which these conductors manage the movement of ions and electrons remain poorly understood. In their study, Collins and his team noted that ions traveled through the conductor at a relatively slow pace. Due to their coordinated movement, this slow ion transport also impeded the electrical current.
“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 address a critical challenge in ion movement, researchers have innovatively engineered a precise nanometer-sized channel exclusively for ions. To effectively attract these ions, they turned to inspiration found in biology. All living organisms, including those in the human body, utilize ion channels to manage the transport of substances, leading Collins’ team to adopt a similar approach with molecules that exhibit hydrophilic (water-loving) and hydrophobic (water-repelling) properties.
The breakthrough began when the team lined the channel with hydrophilic molecules, which drew in the dissolved ions from the water, known as electrolytes. This strategic design allowed ions to traverse the channel at astonishing speeds, exceeding ten times faster than their speed in regular water. This remarkable advancement set a new record for ion transport speed across any material.
Conversely, when the channel was lined with hydrophobic molecules, the ions were dissuaded from entering, instead navigating a much slower path through what could be described as a “rat’s nest.” Collins’ team also uncovered that they could alter the chemical characteristics of the lining molecules, shifting their affinity for the electrolyte. This dynamic capability allows for the channel to open and close, mirroring how biological systems regulate access through cell membranes.
As a result of their work, the team has developed a sensor capable of rapidly identifying a chemical reaction near the channel, as this reaction would activate or deactivate the ion superhighway, generating an electrical pulse that could be interpreted by a computer. This nanoscale detection capability could assist in monitoring environmental pollution or observing the firing of neurons in the body and brain, which is just one of many potential applications of this advancement.
