High-Power X-Rays Reveal How Lithium-Air Batteries Work
© Eva Mutoro and Ethan Crumlin, ALS
A solid-state lithium-air battery (highlighted in orange) is positioned inside a test chamber at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory, in preparation for its testing using X-ray photoelectron microscopy.
Lithium-air batteries have been studied as a potential replacement for lithium-ion batteries because they could store up to four times as much energy for a given weight, but so far, the technology has suffered from a lot of energy loss during charging and discharging that has held it back. A main obstacle to improving the technology has been that researchers didn't really know how the chemical reactions were being carried out within the batteries.
That has now changed thanks to a high-intensity X-ray illumination at Advanced Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBNL) in California. The images made it possible to see the electrochemical reactions taking place at the surface of electrodes, and to show the reactions between lithium and oxygen as the voltage applied to the cell was changed.
The researcher designed a new solid-state version of a lithium-air battery for these tests. In this battery, some lithium ions are drawn in to convert oxygen into lithium peroxide. The images allowed researchers to see a detailed spectra of how the reaction unfolds and they showed that this reaction is reversible on metal oxide surfaces.
According to MIT News, "This study showed that using metal oxides as the oxygen electrode could potentially enable a lithium-air battery to maintain its performance over many cycles of operation. The device used in this study was designed purely for research, not as a practical battery design in itself; if replicated in a real cell, Lu says, such designs could greatly improve the longevity of lithium-air batteries."
These x-rays could give researchers ways to study and improve any type of batteries whose electrochemical reactions were a mystery before, which opens up the possibility of improving energy storage devices across the board. Having robust, reliable energy storage is key to the growth of clean energy adoption, so having a better way to study and improve these systems is quite exciting.