Researchers from MIT and Sandia Nationaal Laboratory have made long-awaited progress in the field of lithium air batteries. This research has brought new insights into the electrochemical reactions that occur when lithium air batteries are charged.

Researchers from MIT and Sandia Nationaal Laboratory have made long-awaited progress in the field of lithium air batteries. This research has brought new insights into the electrochemical reactions that occur when lithium air batteries are charged.

According to spectrum.ieee On May 18, it was reported on the website of www.org.org that lithium air batteries are expected to achieve five to ten times the power storage capacity of traditional lithium-ion batteries. Therefore, many people believe that they may have mastered the key to solving the problem and can transform electric vehicles from a niche market in the automotive industry into a larger market segment.

Undoubtedly, electric vehicles are still the focus of media reports, such as Tesla Model S, which recently won the highest rating in the auto category ever given by Consumer Reports. I guess the editors of Consumer Reports will not mind its 425km range or charging time of several hours.

In order to make electric vehicles more consistent with people's inertial expectations for existing fossil fuel powered vehicles - that is, 650 kilometers of driving range and about two minutes of driving with full fuel for the next 650 kilometers - then the battery technology for powering these all electric vehicles must achieve a great leap.

Although the lithium-ion battery that we use to power electric vehicles has been improving all the time, it has been said for a long time that technically, the initial use of lithium-ion batteries may have been a wrong choice.

If the performance of the battery is comparable to that of fossil fuels, the energy density of the battery needs to reach about 1000 watt hours/kg. At present, even if the performance of the lithium-ion battery we use doubles, it can only reach 400 watt hours/kg. As Steven Chu, the former US Secretary of Energy, said, if battery technology is to compete with internal combustion engines, its power storage capacity will have to be increased to six to seven times that of today's batteries.

It is at this point that lithium air batteries have made a strong debut with their power storage capacity 10 times that of lithium ion batteries. But even today, it is still a major problem to realize the application of this battery anywhere except in a highly controlled laboratory environment.

In the paper (Research on the Electrochemical Oxidation of Lithium Peroxide Observed by In Situ Transmission Electron Microscope) published in the Nano Letters, a journal of the American Chemical Society (ACS), researchers at MIT and Sandia National Laboratory used transmission electron microscopy (TEM) to deeply explore the oxygen evolution reaction, a difficult problem hindering the development of lithium air batteries.

It was in this reaction that researchers observed the oxidation of lithium peroxide (Li2O2) for the first time. Lithium peroxide is a by-product of lithium air battery discharge. The observation shows that lithium peroxide is mainly generated at the interface of the battery substrate, which is made of multi walled carbon nanotubes.

In this position, lithium peroxide blocks the flow of electrons, thus preventing battery charging. However, the researchers also found that when charging, when electrons pass through the carbon nanotubes, the lithium peroxide formed during discharge will gradually shrink. This means that if the electron transfer of batteries can be accelerated, the charging speed of these batteries can also be improved.

"This paper identifies the key constraint - electron transfer." Said Jie Xiao, a researcher at the Pacific Northwest National Laboratory. This example shows us that basic research can significantly improve our ability to solve problems in practical applications. The information provided in this paper will provide insights into the rational design of air electrodes in lithium air batteries.

Although this research still does not point out the way for the application of these batteries outside the laboratory environment, at least one kind of battery technology that is expected to make electric vehicles comparable to fossil fuel driven vehicles is selected as the future road.