Lithium-air batteries have the potential to store much more energy than the lithium-ion batteries we use today, making them ideal for electric vehicles and other high-power needs.
However, their real-world performance has not matched their theoretical potential, and they wear out quickly after only a few charge cycles.
In a new study published in Angewandte Chemie International Edition, researchers in China have developed a simple yet effective solution to these problems: adding a special salt to the battery’s liquid electrolyte.
Lithium-air batteries work differently from lithium-ion batteries.
They use metallic lithium as one electrode (the anode) and air flows through the other electrode (the cathode).
When the battery discharges, lithium ions travel from the anode to the cathode and combine with oxygen to form a compound called lithium peroxide (Li₂O₂).
When recharging, the process reverses, releasing oxygen and returning the lithium ions to the anode.
The problem lies in the formation of Li₂O₂. It is not very conductive, forms slowly, and clogs the battery’s cathode, causing the battery to degrade quickly. Additionally, the high voltage needed for the reactions can damage the electrolyte, leading to side reactions that reduce performance further.
To overcome these challenges, the research team, led by Zhong-Shuai Wu from the Dalian Institute of Chemical Physics, and Xiangkun Ma from Dalian Maritime University, added a new type of catalyst: a salt called 1,3-dimethylimidazolium iodide (DMII).
This salt plays two critical roles.
First, its iodide ions (I⁻) act as a “redox mediator,” transferring electrons efficiently during charging and discharging. This reduces the energy loss in the reactions and speeds up the process.
Second, its DMI⁺ ions create a thin, stable film on the lithium surface that prevents damaging side reactions, protecting the battery and extending its life.
The results are promising. In tests, the new batteries showed much lower energy loss (overpotential), lasted over 960 hours, and maintained stable performance without side reactions.
This breakthrough could bring us closer to high-performance, long-lasting lithium-air batteries, paving the way for powerful energy storage in the future.
