New research findings could lead to safer and more powerful lithium-ion batteries

October 27, 2017, Virginia Commonwealth University
Credit: CC0 Public Domain

Virginia Commonwealth University researchers are working to improve conductivity and safety in lithium-ion batteries, which are used to power many electronic devices around the world, including laptops, iPods, satellites, artificial hearts and cell phones.

Instability in batteries due to liquid-state electrolytes that help carry charges from one battery electrode to another is one hazard scientists can prevent, said Puru Jena, Ph.D., a distinguished professor in the Department of Physics in the College of Humanities and Sciences. Despite this instability, liquid-state electrolytes are commonplace in lithium-ion batteries due to their conductive superiority over more stable solid-state electrolytes.

Theoretical studies by Jena and colleague Hong Fang, a postdoctoral fellow in the Department of Physics, show it is possible to design solid-state electrolytes not only to be as conductive as their liquid counterparts but also very stable. Their findings, which were published in the Proceedings of the National Academy of Sciences this month, could lead to safer and more powerful lithium-ion batteries.

"Theoretically, you can have your cake and eat it too, when it comes to the stability and conductivity," Jena said.

Electrolytes, which are central to a battery, are salts composed of positive and . Positive ions are atoms that have more protons than electrons, while negative ions inversely have more electrons than protons.

In a lithium-ion battery, positive lithium ions flow between electrodes via electrolytes. Lithium ions can flow freely through liquid-state electrolytes but are less mobile in a solid-state , which adversely affects conductivity.

To improve the conductivity in , the researchers produced a computational model in which a single negative ion is removed. Negative cluster ions—groups of atoms with more electrons than protons—replace the absent ion.

The scientists conceptualized a twist on a specific solid-state electrolyte previously tested by other researchers. Originally, the electrolyte, which belongs to a family of crystals called antiperovskites, contained positive ions made of three lithium atoms and one oxygen atom. The positive ions were joined with a single chlorine atom that was a negative ion.

In the computational model, the chlorine atom is replaced by a negative cluster ion created by one boron atom and four fluorine atoms joined to the existing .

Other combinations of negative cluster ions were identified to potentially enhance conductivity.

"Replacing the chlorine ion with cluster ions improves because these ions are larger and allow the lithium ions to move quickly, as if they were in a liquid," Fang said.

Jena and Fang are now in search of collaborators to test their computational model in a laboratory setting for eventual applications.

Explore further: Solid crystals that self-assemble to form channels for an electric current could make safer batteries

More information: Hong Fang et al, Li-rich antiperovskite superionic conductors based on cluster ions, Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1704086114

Related Stories

Building a safer lithium-ion battery

July 12, 2017

Lithium-ion batteries have become an indispensable power source for our proliferating gadgets. They have also, on occasion, been known to catch fire. To yield insight into what goes wrong when batteries fail and how to address ...

Recommended for you

First proof of quantum computer advantage

October 18, 2018

For many years, quantum computers were not much more than an idea. Today, companies, governments and intelligence agencies are investing in the development of quantum technology. Robert König, professor for the theory of ...

Shining light on the separation of rare earth metals

October 18, 2018

Inside smartphones and computer displays are metals known as the rare earths. Mining and purifying these metals involves waste- and energy-intense processes. Better processes are needed. Previous work has shown that specific ...

Placing atoms for optimum catalysts

October 18, 2018

Fuels, plastics, and other products are made using catalysts, materials that drive chemical reactions. To design a better catalyst, scientists must get the right atoms in the right spot. Positioning the atoms can be difficult, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.