Imperfect science of perfect batteries
Metal Tech News - April 6, 2023
Last updated 4/14/2023 at 6:12am
Material scientists look to bridge gap between perfect battery recipe in the lab and mass-producing cells in imperfect world.
Researchers around the world are working feverishly to invent the perfect battery to power the burgeoning electric vehicle revolution. The perfect battery recipe baked up in the lab, however, has little use if it is too complex or expensive for the giga-scale needs of an automotive sector that is replacing 1.4 billion internal combustion engine vehicles with electrified models.
This has Jie Xiao, a leading battery researcher at Pacific Northwest National Laboratory, questioning whether battery scientists need to trade in the thinking cap for a hardhat when coming up with the "perfect battery."
"We are asking the question, 'how can we do research that is relevant to industry manufacturing?'" said Xiao. "We are accustomed to doing fundamental science. But how can the research community support manufacturing science? The questions and challenges are different. Industry doesn't typically have the in-house resources to address these research questions raised during manufacturing."
PNNL Senior Science Communicator Karyn Hede compared commercializing battery recipes invented by materials scientists to mass-producing cookies.
"Imagine the challenge of scaling up a recipe for a dozen cookies to one million cookies. The 'dough' volume becomes much larger, and each batch has to be mixed and baked to an exact temperature and doneness each time, and then repeated exactly the same way day after day," she penned in a recent article.
While the cookies that finally make it to commercial retailers may be good, even great, they will likely not be as good as the ones baked at home while meticulously following grandma's famous recipe.
A different mindset
Equipped with cutting-edge equipment and the highest purity materials available, scientists at universities and national labs are advancing the vanguard when it comes to understanding the properties of the elements on the periodic table and how these newly-discovered characteristics can be harnessed to move the cutting edge of technology forward.
However, it often takes years or decades – and some compromise when it comes to lab quality versus commercial quantity – for these discoveries to make their way into the products we use every day.
"Usually when we do fundamental research, we do not care too much about cost. But for industry manufacturing, both the materials and processing need to be cost efficient," said Xiao. "For example, our tendency in the laboratory is to work with the purest raw materials we can obtain, to get the battery materials with best possible performance."
This scrupulous lab work has resulted in a wide range of lab success when it comes to batteries that pack away more energy, charge faster, and last longer than the cells that are powering today's electric vehicles, smartphones, laptops, kitchen gadgets, lawn tools, and the endless number of other cordless electronic devices being stocked on store shelves and showroom floors.
The global transition to EVs charged with zero-carbon electricity, both of which require energy storage solutions, is increasing the urgency to readying the batteries baked up in the lab for commercial-scale production.
This has Xiao and like-minded scientists rethinking the perfect battery recipe.
"The question we need to be asking now is, 'what is the tolerance of our system to different levels of impurities?' It's a different mindset," the PNNL materials scientist said.
Perfectly imperfect battery
To bridge the gap between lab precision and commercial reality, Xiao proposes that battery laboratories introduce impurities and imperfections into their experiments.
This is a completely new mindset that could even be considered heresy by some scientists that are accustomed to pushing the bounds of perfection as they compete with other labs and universities for the latest and greatest discoveries.
Being a materials scientist herself, however, Xiao still strives to build the perfect battery in an imperfect world.
Toward this natural thrust toward perfection, the PNNL researcher wonders if imperfections can be leveraged to enhance material performance while reducing industry manufacturing costs.
"These are pressing questions that require a shift in research priorities, and a collaborative mindset to work across the cultures of academia and industry," said Xiao.
She and her colleagues have some ideas for making the perfectly imperfect lithium battery – one that stores twice the energy as today's lithium-ion and can be scaled up to commercial production sooner rather than later.
Bridging the gap
Doubling the energy density of lithium batteries would be a game-changer for EVs and the people who drive them. This would mean that future EVs with the same size batteries as today's models could go twice as far on a single charge, or could be made more efficient with smaller and lighter battery packs.
Creating the lithium metal batteries that will make this possible is the prime objective of Battery500 Consortium, a PNNL-led strategic partnership between national labs, universities and industry.
The Battery500 name comes from the 500-watt-hour-per-kilogram battery energy density goal of the consortium. The group believes that batteries with lithium metal anodes paired with metal oxide or sulfur cathodes is the recipe for such an energy-dense battery.
The lithium foils for lithium metal batteries can be made by extrusion and rolling, evaporation, or electrochemical plating. Each of these methods has advantages and disadvantages. However, defects such as pinprick holes, gaps, and even slippage while the sheets are forming can affect performance.
Xiao and her colleagues outline several ideas and opportunities for scientists to come together to explore the fundamental material properties, all to help industrial partners get better performance from their manufacturing processes.
In an article recently published in Nature Energy,, Xiao and her colleagues outline several ideas and opportunities to bridge the gap between lab perfection and processing realities.
The reality of commercial battery manufacturing is that speed and efficiency are required to meet demand and keep costs down.
High speed and volume, however, can trigger quality control issues that are not a problem during the meticulous creation of the battery in the lab.
In the scientific paper, Xiao and her colleagues reviewed four different methods to detect detrimental metal impurities in battery components that can cause battery failure. They also investigated why sensors limit the production speed, and discussed how the combination of online diagnostics and artificial intelligence can enable smart manufacturing.
These and several other research opportunities outlined in the study point the way to scaling up laboratory recipes to good, and maybe even great, high-energy lithium batteries.
"National Laboratories can help industry to identify the scientific problems in manufacturing first by using their unique scientific tools and facilities, address them at the industry-relevant scale, and help lower the risk and cost manufacturers face in scaling up," said Xiao. "We see this article as a service to the scientific and industrial research communities, so they can find ways to come together and revisit what it means to do fundamental research collaboratively in a different way."