Batteries and fuel cells frequently count on a procedure referred to as ion diffusion to function. In ion diffusion, ionized atoms move through strong products, comparable to the procedure of water being taken in by rice when prepared. Just like cooking rice, ion diffusion is extremely temperature-dependent and needs heats to take place quickly.
This temperature level reliance can be restricting, as the products utilized in some systems like fuel cells require to endure heats in some cases in excess of 1,000 degrees Celsius. In a new research study, a group of scientists at MIT and the University of Muenster in Germany revealed a new result, where ion diffusion is boosted while the product stays cold, by just interesting a choose variety of vibrations referred to as phonons. This new technique—which the group refers to as “phonon catalysis”—could lead to a totally new field of research study. Their work was released in Cell Reports Physical Science.
In the research study, the research study group utilized a computational design to identify which vibrations in fact triggered ions to relocation throughout ion diffusion. Rather than increasing the temperature level of the whole product, they increased the temperature level of simply those particular vibrations in a procedure they refer to as targeted phonon excitation.
“We only heated up the vibrations that matter, and in doing so we were able to show that you could keep the material cold, but have it behave just like it’s very hot,” states Asegun Henry, teacher of mechanical engineering and co-author of the research study.
This capability to keep products cool throughout ion diffusion could have a wide variety of applications. In the example of fuel cells, if the whole cell does not require to be exposed to very heats engineers could utilize more affordable products to develop them. This would decrease the expense of fuel cells and would assist them last longer—resolving the concern of the brief life time of lots of fuel cells.
The procedure could likewise have ramifications for lithium-ion batteries.
“Discovering new ion conductors is critical to advance lithium batteries, and opportunities include enabling the use of lithium metal, which can potentially double the energy of lithium-ion batteries. Unfortunately, the fundamental understanding of ion conduction is lacking,” includes Yang Shao-Horn, W.M. Keck Professor of Energy and co-author.
This new work builds on her previous research study, particularly the work of Sokseiha Muy Ph.D. on style concepts for ion conductors, which reveals reducing phonon energy in structures minimizes the barrier for ion diffusion and possibly increases ion conductivity. Kiarash Gordiz, a postdoc working collectively with Henry’s Atomistic Simulation and Energy Research Group and Shao-Horn’s Electrochemical Energy Laboratory, questioned if they could integrate Shao-Horn’s research study on ion conduction with Henry’s research study on heat transfer.
“Using Professor Shao-Horn’s previous work on ion conductors as a starting point, we set out to determine exactly which phonon modes are contributing to ion diffusion,” states Gordiz.
Henry, Gordiz, and their group utilized a design for lithium phosphate, which is frequently discovered in lithium-ion batteries. Using a computational technique referred to as regular mode analysis, in addition to nudged elastic-band estimations and molecular characteristics simulations, the research study group quantitatively calculated just how much each phonon contributes to the ion diffusion procedure in lithium phosphate.
Armed with this understanding, scientists could utilize lasers to selectively delight or warm up particular phonons, instead of exposing the whole product to heats. This technique could open a new world of possibilities.
The dawn of a new field
Henry thinks this technique could lead to the development of a new research study field—one he refers to as “phonon catalysis.” While the new work focuses particularly on ion diffusion, Henry sees applications in chain reactions, stage changes, and other temperature-dependent phenomena.
“Our group is fascinated by the idea that you may be able to catalyze all kinds of things now that we have the technique to figure out which phonons matter,” states Henry. “All of these reactions that usually require extreme temperatures could now happen at room temperature.”
Henry and his group have actually started checking out possible applications for phonon catalysis. Gordiz has actually been taking a look at utilizing the technique for lithium superionic conductors, which could be utilized in tidy energy storage. The group is likewise thinking about applications such as a room-temperature superconductor and even the development of diamonds, which need very high pressure and temperature levels that could be activated at much lower temperature levels through phonon catalysis.
“This idea of selective excitation, focusing only on the parts that you need rather than everything, could be a very big kind of paradigm shift for how we operate things,” states Henry. “We need to start thinking of temperature as a spectrum and not just a single number.”
The scientists prepare to reveal more examples of targeted phonon excitation operating in various products. Moving forward, they hope to show their computational design works experimentally in these products.
Design concepts could point to much better electrolytes for next-generation lithium batteries
Kiarash Gordiz et al, Enhancement of ion diffusion by targeted phonon excitation, Cell Reports Physical Science (2021). DOI: 10.1016/j.xcrp.2021.100431
Massachusetts Institute of Technology
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Phonon catalysis could lead to a new field (2021, May 31)
recovered 31 May 2021
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