Magnesium Goes Mobile: New Energy Storage Tech Threatens Lithium-Ion Dominance

One battery to rule them all: when it comes to energy storage technology, it’s hard to beat lithium-ion. However, the rise of wind and solar has brought forth new motivation to develop new batteries that offer higher energy density at lower cost, and it looks like magnesium is in the running.

In the latest magnesium energy storage development, researchers at Lawrence Berkeley National Laboratory and Argonne National Laboratory have teamed up with MIT to demonstrate, for the first time ever, the potential for magnesium mobility in a battery.

The Magnesium Energy Storage Problem…

Magnesium offers two potential advantages over lithium-ion, on cost and electrical current. That’s because magnesium (Mg) is a multivalent ion, as Berkeley Lab explains:

Whereas a Li-ion with a charge of +1 provides only a single electron for an electrical current, a Mg-ion has a charge of +2, which means Mg-ions, in principle, can provide twice the electrical current of Li-ions if present with the same density.

So, what’s the problem? In the energy storage field there ain’t no such thing as a free lunch:

The catch for multivalent ions is that their increased charge draws more attention to them — they become surrounded in the battery’s electrolyte by other oppositely charged ions and solvent molecules — which can slow down their motion and create energetic penalties to exiting the electrolyte for the electrodes…

…And The Solution

Got all that? The basic problem is that the liquid electrolyte in a Mg-ion battery tends to corrode other elements in the system.

The good news is that Mg-ion technology is so new that researchers haven’t reached the end of the rope yet. In fact, the new study gives the boot to liquid electrolyte altogether and goes straight to cutting edge solid state energy storage technology.

That’s quite a leap of faith, considering that the conventional science indicates that magnesium moves sl-o-w-ly through most solids.

You can get all the details from Nature Communications under the title, “High magnesium mobility in ternary spinel chalcogenides.”

For those of you on the go, the research team developed a whole new class of solid conductors and settled on magnesium scandium selenide spinel, which performs about as well as a lithium-ion battery solid state electrolyte.

The collaborative research effort pulled together resources at Berkeley Lab with additional computer resources from MIT. Researchers at Argonne documented the structure and function of the new material using nuclear magnetic resonance spectroscopy (NMR).

If you’ve ever had an MRI, NMR is kind of the same but the equipment can be “tuned” to detect other elements aside from hydrogen.

The NMR part of the new study essentially confirmed the “fast magnesium hopping” theory behind the new energy storage material. Co-Author Baris Key of Argonne credits the collaborative resources of JCESR (the Joint Center for Energy Storage Research) with the achievement:

“…The solid state NMR experiments for this chemistry were very challenging and would not be possible without dedicated resources and a funding source such as JCESR. As we’ve shown in this study, an in-depth understanding of short- and long-range structure and ion dynamics will be the key for magnesium ion battery research.”

For the record, lead authors on the study are Berkeley lab postdoctoral fellows Pieremanuele Canepa and Shou-Hang Bo. Other co-authors are Juchaun Li of Berkeley Lab, William Richards and Yan Wang of MIT, and Tan Shi and Yaosen Tian of UC Berkeley.

If we lefty anybody out, drop us a note in the comment thread.

#ThanksObama!

Another study co-author, Gopalakrishnan Sai Gautam of Princeton University (formerly of Berkeley Lab), also gave props to JCESR:

“The work shows the importance of using a variety of theoretical and experimental techniques in a highly collaborative environment to make important fundamental discoveries,” he said.

JCER was established in 2012 under the Obama Administration, as enthusiastically noted by CleanTechnica:

The Department of Energy has announced a major new initiative designed to rocket the U.S. EV battery industry into global leadership, vastly improving the prospects for average car buyers to wrap their hands around the steering wheels of affordable, long-range EVs some time in the not too distant future.

So, Now What?

Next steps include testing the new material in a full energy storage system, AKA a battery. That’s going to be rather complicated. Berkeley Lab points out that the new study pinpointed two related energy storage issues having to do with anti-site defects and the magnesium conductivity, both of which will influence the direction of further research on solid state electrolytes.

As for rocketing to world leadership, that’s an iffy prospect these days considering that President* Trump is not exactly a fan of clean tech.

So far this year the US Energy Department has been soldiering on with its clean tech mission, which Energy Secretary Rick Perry has been vigorously promoting. In one recent development, last week the agency signed off on a major renewable energy project, a new coal-killing hydropower transmission line for New England.

However, Secretary Perry has also proposed a new rate structure to protect aging coal power plants. FERC, the Federal Energy Regulatory Commission, will have to take responsibility for the final decision on that.

The FERC shoe could drop by December 11, so stay tuned.

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*As of this writing.

Photo (cropped): “Argonne scientist Baris Key, shown on left at work in his nuclear magnetic resonance lab, worked with researchers at Berkeley Lab on the discovery of the fastest ever magnesium-ion solid-state conductor” by Argonne National Laboratory.