Argonne MEF researchers scale up production of new molecule that protects Li-ion batteries from thermal overcharge

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Argonne MEF researchers scale up production of new molecule that protects Li-ion batteries from thermal overcharge

15 September 2011

Researchers at the new Material Engineering Facility (MEF) at the US Department of Energy’s (DOE) Argonne National Laboratory have successfully scaled up the production of a new molecule that protects advanced lithium-ion batteries from thermal overcharge.

When Argonne materials scientist Khalil Amine and chemists Zhengcheng Zhang and Lu Zhang invented a redox shuttle additive material known as 2,5-di-tert-butyl-1,4-bis(2-methoxyethoxy)benzene (DBBB), the amount of the molecule they produced was sufficient for scientific testing and validation at the laboratory bench scale. But their process yielded too little material—less than 1 gram—for a company that may be interested in licensing and manufacturing the material to validate and test.

DBBB
Overcharge is a common factor that can lead to serious safety issue in automotive applications. Protections against overcharge can include electronic devices with specific chargers, or additives such as a redox shuttle.
Redox shuttles can be reversibly oxidized and reduced at specific potential slightly higher than the end-of-charge potential of the positive electrode.
Dr. Amine and his colleagues developed two new redox shuttles for overcharge protection; the DBBB redox shuttle showed excellent electrochemical stability during overcharge testing.
Normal cycle tests have confirmed that addition of the DBBB redox shuttle to lithium-ion cells does not negatively affect the cell performance. Heat generation was observed during overcharge process, and the estimate of electricity-to-heat conversion rate is more than 93%.

Applied researchers in Argonne’s Advanced Battery Materials Synthesis and Manufacturing Research & Development Program took the formula and developed an improved, scalable process that created 1,576 grams in a single batch—enough to study and validate in a real battery cell, said Argonne’s Greg Krumdick, a systems engineer whose team developed the scale-up process.

The scale-up of a specialty material like DBBB is non-trivial; it is not a matter of multiplying the amount of a chemical formulation by 1,000 or 10,000 or more to make larger quantities of a molecule. Other considerations such as time, temperature, concentration, mixing speeds and even the chemical ingredients themselves that do not come up when making very small amounts of a material arise when attempting to make vastly larger volumes for commercial testing and mass market production.

Unless you have a process to make a material in sufficient quantities, you simply can’t get enough of the material. It is often wrongly assumed that industry will do the scale-up work, but most companies don’t want to make the significant financial investment required to develop the scale-up process. It’s too risky, especially if you don’t know if it will be economical to make the material at scale.
—Greg Krumdick

That is where the process engineering and scale-up expertise and facilities of Argonne’s federally funded Advanced Battery Materials Synthesis and Manufacturing Research & Development Program are brought to bear.

The goal of process scale up is to find economical ways to make a material. The bench scale process used to discover DBBB would have cost 20 times more and generated 50 times as much waste as the scaled-up process to make one kilogram. The new process also is three times faster.

However, it was never intended to use the bench scale process to make commercial quantities of materials, Krumdick said.

When discovering new materials, it’s not your objective to be sure it is made economical; it’s to make it quickly. Once a new material has been discovered and is shown to have promise, it’s my group’s job to scale it up, meaning find economical ways to make large volumes of the materials.

After finishing work on DBBB, we had made a kilogram scale batch that was chemically analyzed and its electrochemical performance characterized and was found to be identical to the initial material synthesized. The new process is also highly reproducible in yield and purity from batch to batch.
—Greg Krumdick

Krumdick worked with Krzystof Pupek and Trevor Dzwiniel—both of who came from the pharmaceutical industry, which routinely develops scale-up processes—to scale-up DBBB at the Material Engineering Facility (MEF), where the scale-up work was done.

DOE invested $5.8 million from the American Recovery and Reinvestment Act to help fund MEF’s construction to help close the lag time between innovation and commercialization. The US Department of Defense (DoD) provided another $4 million toward MEF construction.

The MEF is not yet fully constructed. The facility is expected to be completed in January and will contain three pilot labs and high-bays for continuous batch production of large volumes—up to 100 kilograms—of specialty materials for industry validation, said Krumdick, who oversees MEF construction.

Argonne plans make the MEF a quasi-user facility that will be accessible to other R&D organizations and companies, said Jeff Chamberlain, who leads Argonne’s energy storage research initiative. The facility and the close teaming of scientists and engineers are part of a full-circle approach that Argonne employs to help industry move US energy innovations into the marketplace more quickly.

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