Researchers at the University of Michigan and Samsung’s Advanced Materials Lab have demonstrated a new approach to making chemically complex materials for battery manufacturing.
Thanks to the technique of mixing unconventional ingredients in the correct order, new chemistries for battery manufacturing, semiconductors, and more could be more accessible to manufacture.
Their new recipes use unconventional ingredients to make battery materials with fewer impurities, requiring fewer costly refinement steps and increasing economic viability.
“Over the past two decades, many battery materials with enhanced capacity, charging speed and stability have been designed computationally but have not made it to market,” said Wenhao Sun, the Dow Early Career Professor of Materials Science and Engineering at U-M and corresponding author of the study.
“A simple material is often a good starting point, but when you add a little bit of compound A and a little bit of compound B, magic happens, and you get significant improvements in capacity or charging rate.
“However, these chemically complex materials are often difficult to manufacture at scale with high purity.”
A reliable method for impurity-free materials
Battery materials are typically made by mixing several different oxide powders and firing them in an oven.
However, these powders react in a sequence rather than all at the same time. The first two ingredients to react are usually those that release the most energy upon reacting.
The first reaction results in an intermediate compound that then reacts with the remaining powder, and so on, until no more reactions are possible.
If the chemical bonds in the intermediate compounds are difficult to break, they might not fully react with the other ingredients. When they don’t fully react, the intermediates hang around as undesired impurities in the final material.
“We designed a strategy to make impurity-free materials more reliably,” said Jiadong Chen, the first author of the study and a U-M doctoral student in materials science and engineering and scientific computing.
“The trick is to work with only two ingredients at a time and deliberately make unstable intermediates that will react completely with the remaining ingredients for effective battery manufacturing.”
A new automatic lab for better battery manufacturing
To test this strategy, the team designed 224 different recipes to create 35 different known materials containing elements used in today’s batteries and next-generation ‘beyond-lithium’ batteries.
The researchers then partnered with Samsung Semiconductor’s Advanced Materials Lab in Cambridge, Massachusetts, to test if their recipes produced these 35 materials with fewer impurities than conventional recipes. Samsung’s automated robotic lab can synthesise up to 24 different battery materials every 72 hours.
Robotic arms handle the ingredients and operate the lab equipment that assesses the purity of the resulting materials.
Meanwhile, computers automatically record the results of each experiment, creating a database that researchers can use to determine which recipes are most efficient for battery manufacturing.
Chen explained: “With the automatic lab, we could broadly test our hypothesis on diverse battery chemistries.”
The experiments confirmed that the new recipes with unstable ingredients tended to produce cleaner products. The new recipes improved the materials’ purity by up to 80%, and six of the target materials could only be made with new recipes.
The team’s report detailed blueprints for the robotic lab, which Sun hopes will enable more chemistry labs to adopt robotic labs for science and materials manufacturing.
“We need more data—not just from successful recipes but also the unsuccessful ones—to improve battery manufacturing strategies. More robotic labs will help generate the needed data,” he concluded.
