The rechargeable lithium-ion batteries available today are good; however they could be a lot better in the future.
The Researchers from
University of Illinois at Chicago and Argonne National Laboratory have come to this conclusion after extensive studies using real-time transmission electron microscopy (TEM). They explain in Nature Communications that the method is the most effective way to comprehend the electrochemical reactions of lithium-ion batteries and to learn how the batteries can be altered to become safer, longer lasting, stronger and cheaper.
Reza Shahbazian-Yassar, left, and Yifei Yuan (credit: University of Illinois at Chicago)
“Despite widespread use, rechargeable ion batteries face various materials and interfacial challenges that exclude them from high power and high-performance applications,” says Reza Shahbazian-Yassar, Associate Professor of Mechanical and Industrial Engineering and one of the Co-authors on the paper that includes Khalil Amine and Jun Lu of Argonne.
Lithium-ion batteries are frequently used in portable and home electronics, and in a few motor vehicles. They function when lithium ions move from the negative electrode to the positive electrode during discharge and back when charging. And while the market is estimated to go beyond $77 billion by 2024, according to Transparency Market Research, the Researchers say that numerous questions need to be answered before better batteries can be designed.
There are many scientific challenges, and we want to learn what causes the batteries to fade during cycling; why lower temperatures cause a poor power supply; why it may overheat and explode; and why the batteries become unstable if overcharged. Sometimes good materials are made but they are not safe. Sometimes they are made safe but they don’t deliver enough energy to work. We want to find a happy medium.
Reza Shahbazian-Yassar, Associate Professor of Mechanical and Industrial Engineering and Co-author on the paper
For example, Shahbazian-Yassar says the lithium-ion batteries that are used nowadays fall short of reaching the longevity or high-energy density needed to power electric vehicles while still matching the performance of vehicles driven by internal combustion engines. Thus, new combinations of electrochemicals such as lithium and silicon, and lithium and oxygen, are being analyzed because of their ability to hold and produce higher densities of energy.
Shahbazian-Yassar and Yifei Yuan, a Postdoctoral Researcher working together at UIC and Argonne and the study’s Lead Author, used real-time TEM to examine the batteries because the method allows Researchers to alter specimens — either through straining, heating, or other uncontrolled processes — in a measured way.
There are several advantages to performing research in situ, or in real time, Shahbazian-Yassar said. A single in situ experiment offers an uninterrupted view of a process and its variations, instead of using a number of samples; and specific and comprehensive movements can be measured.
Besides lithium, which is a light but very reactive material with limited supply in the earth, Researchers are keen on exploring substitute charge carriers such as sodium, due to its abundance in the earth and relatively light atomic weight, and multivalent ions with high-energy density, such as calcium, magnesium and aluminum.
The components of batteries must be changed and new designs and materials must be used that cost less. The batteries need to deliver more energy and better performance, providing double or triple the amount of energy density they now provide. Overall, if you look at the last 10 years, the battery cost is reducing, but it’s still not in the range we are hoping for. There needs to be high standards when developing the next generation of lithium-ion batteries, and we’re working towards that.
Reza Shahbazian-Yassar , Associate Professor of Mechanical and Industrial Engineering and Co-author on the paper
The research was funded by the U.S. Department of Energy under contract DE-AC0206CH11357 with support from the Vehicle Technologies Office and the Department of Energy’s Office of Energy Efficiency and Renewable Energy. The research was also financially supported by the National Science Foundation, award number DMR-1620901.