Longer lasting lithium-air batteries

Dr Kyeongjae Cho, a researcher from UT Dallas, has discovered new catalyst materials for lithium-air batteries that jumpstart efforts at expanding battery capacity. His team’s research, published in the journal Nature Energy, could open the door to phone and car batteries that last five times longer than current ones.

Lithium-air (or lithium-oxygen) batteries ‘breathe’ oxygen from the air to power the chemical reactions that release electricity, rather than storing an oxidiser internally like lithium-ion batteries do. Because of this, lithium-air batteries boast an energy density comparable to gasoline — with theoretical energy densities as much as 10 times that of current lithium-ion batteries — giving them potential for storage of renewable energy. For example, at one-fifth the cost and weight of those presently on the market, a lithium-air battery would allow an electric car to drive 640 km on a single charge and a mobile phone to last a week without recharging.

Practical attempts to increase lithium-air battery capacity so far have not yielded great results, Cho said, despite efforts from major corporations and universities. Until now, these attempts have resulted in low efficiency and poor rate performance, instability and unwanted chemical reactions.

Now, Cho and graduate student Yongping Zheng have introduced research that focuses on the electrolyte catalysts inside the battery, which, when combined with oxygen, create chemical reactions that create battery capacity. They said soluble-type catalysts possess significant advantages over conventional solid catalysts, generally exhibiting much higher efficiency. In particular, they found that only certain organic materials can be utilised as a soluble catalyst.

With this in mind, Cho and Zheng collaborated with researchers at Seoul National University to create a new catalyst for the lithium-air battery called dimethylphenazine, which possesses higher stability and increased voltage efficiency. According to Zheng, “The catalyst should enable the lithium-air battery to become a more practical energy storage solution.”

While it could take five to 10 years before the research translates into new batteries that can be used in consumer devices and electric vehicles, Cho believes his study is “a major step” which will hopefully “revitalise the interest in lithium-air battery research, creating momentum that can make this practical, rather than just an academic research study”. He said he has been providing research updates to car manufacturers and telecommunications companies and that there has been interest in his studies.