University of Michigan researchers set hurdles for solid-state Li-metal batteries
In a perspective article in the newspaper Joule, researchers at the University of Michigan discuss the main questions facing lithium-metal solid-state batteries. To develop the questions, they worked closely with leaders in the automotive industry.
Major automakers are moving into electric vehicles this year, and many advertisers plan to phase out internal combustion engine cars in the coming years. Lithium-ion batteries enabled the first electric vehicles and they remain the most common power supply for the latest models coming off the assembly lines.
These lithium-ion batteries are approaching their peak performance in terms of EV range on a single charge. They require a heavy and bulky battery management system, without which there is a risk of fire on board. By using lithium metal for the battery anode with ceramic for the electrolyte, the researchers demonstrated the potential to double the EV range for a battery of the same size while significantly reducing the risk of fires.
Huge strides have been made in advancing lithium-metal solid-state batteries over the past decade. However, several challenges remain on the way to commercialization of the technology, especially for electric vehicles.
—Jeff Sakamoto, corresponding co-author
The questions that need to be answered to take advantage of this potential are:
How can we produce ceramics, which are brittle, in the massive, paper-thin sheets that lithium metal batteries need?
Does the use of ceramics by lithium metal batteries, which require energy to heat them to over 2,000 degrees Fahrenheit during manufacture, outweigh their environmental benefits in electric vehicles?
Can the ceramics and the manufacturing process be adapted to account for defects, such as cracking, in a way that does not require battery manufacturers and automakers to radically reorganize their operations?
A lithium-metal solid-state battery would not require the heavy, bulky battery management system lithium-ion batteries need to maintain durability and reduce the risk of fire. How will reducing the mass and bulk of the battery management system – or removing it altogether – affect the performance and durability of a solid-state battery?
The lithium metal must be in constant contact with the ceramic electrolyte, which means that additional material is needed to apply pressure in order to maintain contact. What will the additional hardware mean for battery performance?
Sakamoto, which has its own lithium metal semiconductor battery start-up (Zakuro), says the technology is experiencing a moment right now. But the enthusiasm that drives the moment, he says, must not get ahead.
Rigorous testing and data analysis, as well as transparency in research, are needed, according to the UM team.
In this context, we stress the importance of a better mechanistic understanding of these systems using consistent test protocols and data analysis methods, guided by practical inputs and design criteria offered by automakers and other industrial parts.
—Wang et al.
Michael J. Wang, Eric Kazyak, Neil P. Dasgupta, Jeff Sakamoto (2021) “Transition of semiconductor batteries from the laboratory to the market: linking electrochemechanics to practical considerations” Joule doi: 10.1016 / j.joule.2021.04.001