Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

No more trial-and-error when choosing an electrolyte for metal-air batteries

15.07.2019

Engineering researchers demonstrate how electrolytes for alkali-metal air batteries can be selected using a single, easy-to-measure parameter

Metal-air batteries have been pursued as a successor to lithium-ion batteries due to their exceptional gravimetric energy densities. They could potentially enable electric cars to travel a thousand miles or more on a single charge.


This graph shows the correlations between three parameters that lead to a single descriptor which provides a rational basis to design electrolyte compositions for high-power alkali metal-oxygen batteries, including potassium-air batteries. This research from the McKelvey School of Engineering will help engineers find the right electrolyte for new and improved batteries, including potassium-air batteries.

Credit: Ramani lab

A promising new member of the alkali-metal-air battery family is the potassium-air battery, which has more than three times the theoretical gravimetric energy density of lithium ion batteries.

A key challenge in designing potassium-air batteries is choosing the right electrolyte, the liquid which facilitates the transfer of ions between the cathode and anode.

Typically, electrolytes are chosen using a trial-and-error approach based on rules of thumb correlating several electrolyte properties, followed by exhaustive (and time consuming) testing of several electrolyte candidates to see if the desired performance is achieved.

Researchers from Washington University in St. Louis, led by Vijay Ramani, the Roma B. and Raymond H. Wittcoff Distinguished Professor of Environment & Energy at the McKelvey School of Engineering, have now shown how electrolytes for alkali-metal air batteries can be chosen using a single, easy-to-measure parameter.

Their work was published July 8 in the Proceedings of the National Academy of Sciences.

Ramani's team studied the fundamental interactions between the salt and solvent in the electrolyte and show how these interactions can influence overall battery performance. They developed a novel parameter, namely the "Electrochemical" Thiele Modulus, a measure of the ease of ion transport to and reaction at an electrode surface.

This research documents the first time that the Nobel Prize-winning Marcus-Hush theory of electron transfer has been used to study the impact of electrolyte composition on the movement of ions through the electrolyte, and their reaction at the surface of the electrode.

This Thiele Modulus was shown to exponentially decrease with increasing solvent reorganization energy -- a measure of the energy needed to modify the solvation sphere of a dissolved species. Thus, the solvent reorganization energy could be used to rationally select electrolytes for high performance metal-air batteries. No more trial-and-error.

"We started out trying to better understand the influence of the electrolyte on the oxygen reduction reaction in metal-air battery systems," said Shrihari Sankarasubramanian, a research scientist on Ramani's team and lead author of the study.

"We ended up showing how the diffusion of ions in the electrolyte and the reaction of these ions on the electrode surface are both correlated to the energy needed to break the solvation shell around the dissolved ions."

"Showing how a single parameter descriptor of the solvation energy correlates with both ion transport and surface reaction kinetics is a breakthrough advance," Ramani said. "It will allow us to rationally develop new high-performance electrolytes for metal-air batteries."

###

Joshua Kahky, a rising junior in the Department of Energy, Environmental and Chemical Engineering, is second author of the study. He helped carry out the study as an undergraduate summer intern in Ramani's lab.

Brandie Jefferson | EurekAlert!
Further information:
https://source.wustl.edu/2019/07/no-more-trial-and-error-when-choosing-an-electrolyte-for-metal-air-batteries/
http://dx.doi.org/10.1073/pnas.1901329116

More articles from Power and Electrical Engineering:

nachricht Hot electrons harvested without tricks
18.11.2019 | University of Groningen

nachricht New laser opens up large, underused region of the electromagnetic spectrum
15.11.2019 | Harvard John A. Paulson School of Engineering and Applied Sciences

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Atoms don't like jumping rope

Nanooptical traps are a promising building block for quantum technologies. Austrian and German scientists have now removed an important obstacle to their practical use. They were able to show that a special form of mechanical vibration heats trapped particles in a very short time and knocks them out of the trap.

By controlling individual atoms, quantum properties can be investigated and made usable for technological applications. For about ten years, physicists have...

Im Focus: Images from NJIT's big bear solar observatory peel away layers of a stellar mystery

An international team of scientists, including three researchers from New Jersey Institute of Technology (NJIT), has shed new light on one of the central mysteries of solar physics: how energy from the Sun is transferred to the star's upper atmosphere, heating it to 1 million degrees Fahrenheit and higher in some regions, temperatures that are vastly hotter than the Sun's surface.

With new images from NJIT's Big Bear Solar Observatory (BBSO), the researchers have revealed in groundbreaking, granular detail what appears to be a likely...

Im Focus: New opportunities in additive manufacturing presented

Fraunhofer IFAM Dresden demonstrates manufacturing of copper components

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Dresden has succeeded in using Selective Electron Beam Melting (SEBM) to...

Im Focus: New Pitt research finds carbon nanotubes show a love/hate relationship with water

Carbon nanotubes (CNTs) are valuable for a wide variety of applications. Made of graphene sheets rolled into tubes 10,000 times smaller than a human hair, CNTs have an exceptional strength-to-mass ratio and excellent thermal and electrical properties. These features make them ideal for a range of applications, including supercapacitors, interconnects, adhesives, particle trapping and structural color.

New research reveals even more potential for CNTs: as a coating, they can both repel and hold water in place, a useful property for applications like printing,...

Im Focus: Magnets for the second dimension

If you've ever tried to put several really strong, small cube magnets right next to each other on a magnetic board, you'll know that you just can't do it. What happens is that the magnets always arrange themselves in a column sticking out vertically from the magnetic board. Moreover, it's almost impossible to join several rows of these magnets together to form a flat surface. That's because magnets are dipolar. Equal poles repel each other, with the north pole of one magnet always attaching itself to the south pole of another and vice versa. This explains why they form a column with all the magnets aligned the same way.

Now, scientists at ETH Zurich have managed to create magnetic building blocks in the shape of cubes that - for the first time ever - can be joined together to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

High entropy alloys for hot turbines and tireless metal-forming presses

05.11.2019 | Event News

 
Latest News

Structure of a mitochondrial ATP synthase

19.11.2019 | Life Sciences

The measurements of the expansion of the universe don't add up

19.11.2019 | Physics and Astronomy

Ayahuasca compound changes brainwaves to vivid 'waking-dream' state

19.11.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>