Friday , February 26 2021

Technology: the "#" highway & # 39; of protons transport can smooth the way to the best high power batteries (report)



Researchers from Oregon State University have discovered that a chemical mechanism that was described more than two centuries ago has the potential to revolutionize energy storage for high power applications , such as vehicles or electric networks.

The research team led by Xiulei (David) Ji of the College of Sciences of OSU, together with collaborators of the National Laboratory of Argonne, the University of California Riverside and the Oak Ridge National Laboratory, are the first to show that diffusion may not be necessary to carry ionic loads within a solid hydrated structure of a battery electrode.

"This discovery will potentially change the paradigm of high power electrical storage with new design principles for electrodes," said Xianyong Wu, OSU's postdoctoral academic and first author of the " Article #.

The results were published today in Energy of nature.

"Having the faradic electrodes that allow the energy density of the battery and the power of the condenser with an excellent life cycle of the cycle have been a great challenge," said Ji, associate professor of chemistry. "So far, most of the attention has been devoted to metal ions: starting with the lithium and looking below the periodic table."

The collaboration team, however, looked at the unique hydrogen proton and also looked back on Theodor von Grotthuss, a Lithuanian chemist born in Germany in 1806, who wrote the theory of the transport of load in the electrolytes.

Von Grotthuss was only 20 years old, and lived in a region besieged by a political upheaval, when he published "Memory on the decomposition of water and bodies that he maintains in solution through galvanic electricity" in a magazine French scientist.

"In the confusion of his time and place, he managed to make this great discovery," Ji said. "It was the earliest to find out how the electrolyte works, and described what is now known as the Grotthuss mechanism: proton transferred by cooperative split and formation of hydrogen bonds and links OH covalents within the hydrogen bonding network of water molecules. "

Here's how it works: The electrical charge is made when a hydrogen atom that crosses two water molecules "changes its loyalty" from one molecule to another, explains Wu.

"The switch initiates one of the hydrogen atoms covalently bonded to the second molecule, triggering a chain of similar displacements through the hydrogen bonding network," he said. "The movement is like a cradle of Newton: the correlated local displacements lead to the transport of long protons, which is very different from the conduct of metallic ions in liquid electrolytes, where the solvated ions spread long distances individually ".

He added: "Cooperative vibrations of the hydrogen bond and hydrogen-oxygen covalent bonds virtually deliver a proton from a chain molecule endpoint, Water to the other end without mass transfer within the water chain ".

The molecular relay race is the essence of a highly efficient charge conduit, he said.

"This is the beauty of that," Ji said. "If this mechanism is installed in battery electrodes, the proton should not squeeze through narrow holes in crystal structures. If we design materials in order to facilitate this type of conduction, this conduit is so ready, we have this magical freeway of protons integrated in the network ".

In his experiment, Ji, Wu and his colleagues revealed the extremely high performance of a prussian Blue analog, the Turnbull blue, known for the dye industry. The only network of adjacent lattice network within the electrode network demonstrates the "greatness" promised by the Grotthuss mechanism.

"Computational scientists have made great progress in understanding how the proton jump actually occurs in water," said Ji. "But Grotthuss's theory was never explored to take advantage of energy storage in detail, especially in a well-defined redox reaction, which was intended to materialize the impact of # 39; this theory ".

While he was very enthusiastic about his findings, Ji warns that there is still work to achieve an ultra-fast loading and unloading in batteries that are practical for transporting or storing energy from the network.

"Without the proper technology that involves researching scientific materials and electrical engineers, that's all purely theoretical," he said. "Can it have a secondary battery charge or discharge? In theory we have shown it, but to realize it on consumer devices, it could be a long journey of engineering. At the moment, the battery community focuses on lithium ion, sodium and other metal ions, but probably the protons are the most intriguing freight operators with ample unknown potential to realize. "

The National Science Foundation and the US Department of Energy supported this research.


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