Nuclear magnetic resonance spectroscopy (MRS) is a technique that detects radio-frequency electromagnetic signals from atomic nuclei within molecules. This method enables observers to measure concentrations of certain chemicals without altering the source. MRS previously allowed neurologists to ‘peer’ into human brains. Now it seems they can do that with lithium-metal batteries too.
Magnetic Resonance Spectroscopy Accelerates Battery Design
A team at Department of Chemical Engineering, Columbia University, New York used MRS to investigate lithium-metal batteries. These have exceptionally high-charge density initially, but rapidly lose their capacity for storage.
“We believe that … with the data we’ve pulled together, we can help accelerate the design of lithium metal batteries,’’ a team member told Interesting Engineering. “And help make them safe for consumers, which folks have been trying to do for more than four decades.”
Battery scientists have known for a while how the passivation layer’s chemistry affects lithium-metal battery performance:
- The chemistry affects the movement of lithium ions during charging and discharging.
- This determines whether metal filament fibers accumulate, affecting battery performance.
Battery researchers have been unable to observe the chemistry directly until now. “If we had this information,” they say. “We could start to draw connections to specific … structures and properties that lead to high-performance batteries.”
What the Columbia University Chemical Engineers Saw
The team from Columbia University, New York were able to directly determine the following critical information:
- Lithium-ion movement speed at the interface between the lithium metal anode and its passivation layer.
- The chemical compounds present at that point, during lithium-metal battery charging and recharging.
This is a significant improvement over other methods, which are only able to provide detailed images of the solid electrolyte interface layer itself. Understanding the structural changes inside batteries should be valuable input to designing better lithium-metal batteries. That’s batteries that retain their capacity far longer.
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