Scientists Develop A Battery That Can Run For More Than A Decade

Credit: Harvard University

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new flow battery that stores energy in organic molecules dissolved in neutral pH water. This new chemistry allows for a

• non-toxic,
• non-corrosive battery
• with an exceptionally long lifetime and
• offers the potential to significantly decrease the costs of production.

The research, published in ACS Energy Letters, was led by Michael Aziz, the Gene and Tracy Sykes Professor of Materials and Energy Technologies and Roy Gordon, the Thomas Dudley Cabot Professor of Chemistry and Professor of Materials Science.

A Neutral pH Aqueous Organic–Organometallic Redox Flow Battery with Extremely High Capacity Retention
Eugene S. Beh†‡ , Diana De Porcellinis†#, Rebecca L. Gracia∥, Kay T. Xia∥, Roy G. Gordon*†‡, and Michael J. Aziz*†

† John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
‡ Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
# Department of Chemical Science and Technologies, University of Rome “Tor Vergata”, 00133 Rome, Italy
∥ Harvard College, Cambridge, Massachusetts 02138, United States
ACS Energy Lett., 2017, 2 (3), pp 639–644
DOI: 10.1021/acsenergylett.7b00019
Publication Date (Web): February 7, 2017
Copyright © 2017 American Chemical Society
*E-mail: gordon@chemistry.harvard.edu., *E-mail: maziz@harvard.edu.

Abstract

We demonstrate an aqueous organic and organometallic redox flow battery utilizing reactants composed of only earth-abundant elements and operating at neutral pH. The positive electrolyte contains bis((3-trimethylammonio)propyl)ferrocene dichloride, and the negative electrolyte contains bis(3-trimethylammonio)propyl viologen tetrachloride; these are separated by an anion-conducting membrane passing chloride ions. Bis(trimethylammoniopropyl) functionalization leads to ∼2 M solubility for both reactants, suppresses higher-order chemical decomposition pathways, and reduces reactant crossover rates through the membrane. Unprecedented cycling stability was achieved with capacity retention of 99.9943%/cycle and 99.90%/day at a 1.3 M reactant concentration, increasing to 99.9989%/cycle and 99.967%/day at 0.75–1.00 M; these represent the highest capacity retention rates reported to date versus time and versus cycle number. We discuss opportunities for future performance improvement, including chemical modification of a ferrocene center and reducing the membrane resistance without unacceptable increases in reactant crossover. This approach may provide the decadal lifetimes that enable organic–organometallic redox flow batteries to be cost-effective for grid-scale electricity storage, thereby enabling massive penetration of intermittent renewable electricity.

Flow batteries store energy in liquid solutions in external tanks—the bigger the tanks, the more energy they store. Flow batteries are a promising storage solution for renewable, intermittent energy like wind and solar but today’s flow batteries often suffer degraded energy storage capacity after many charge-discharge cycles, requiring periodic maintenance of the electrolyte to restore the capacity.

By modifying the structures of molecules used in the positive and negative electrolyte solutions, and making them water soluble, the Harvard team was able to engineer a battery that loses only one percent of its capacity per 1000 cycles.

“Lithium ion batteries don’t even survive 1000 complete charge/discharge cycles,” said Aziz.

“Because we were able to dissolve the electrolytes in neutral water, this is a long-lasting battery that you could put in your basement,” said Gordon. “If it spilled on the floor, it wouldn’t eat the concrete and since the medium is noncorrosive, you can use cheaper materials to build the components of the batteries, like the tanks and pumps.”

This reduction of cost is important. The Department of Energy (DOE) has set a goal of building a battery that can store energy for less than $100 per kilowatt-hour, which would make stored wind and solar energy competitive to energy produced from traditional power plants.

“If you can get anywhere near this cost target then you change the world,” said Aziz. “It becomes cost effective to put batteries in so many places. This research puts us one step closer to reaching that target.”

“This work on aqueous soluble organic electrolytes is of high significance in pointing the way towards future batteries with vastly improved cycle life and considerably lower cost,” said Imre Gyuk, Director of Energy Storage Research at the Office of Electricity of the DOE. “I expect that efficient, long duration flow batteries will become standard as part of the infrastructure of the electric grid.”

The key to designing the battery was to first figure out why previous molecules were degrading so quickly in neutral solutions, said Eugene Beh, a postdoctoral fellow and first author of the paper. By first identifying how the molecule viologen in the negative electrolyte was decomposing, Beh was able to modify its molecular structure to make it more resilient.

Next, the team turned to ferrocene, a molecule well known for its electrochemical properties, for the positive electrolyte.

“Ferrocene is great for storing charge but is completely insoluble in water,” said Beh. “It has been used in other batteries with organic solvents, which are flammable and expensive.”

But by functionalizing ferrocene molecules in the same way as with the viologen, the team was able to turn an insoluble molecule into a highly soluble one that could also be cycled stably.

“Aqueous soluble ferrocenes represent a whole new class of molecules for flow batteries,” said Aziz.

The neutral pH should be especially helpful in lowering the cost of the ion-selective membrane that separates the two sides of the battery. Most flow batteries today use expensive polymers that can withstand the aggressive chemistry inside the battery. They can account for up to one third of the total cost of the device. With essentially salt water on both sides of the membrane, expensive polymers can be replaced by cheap hydrocarbons.

This research was coauthored by Diana De Porcellinis, Rebecca Gracia, and Kay Xia. It was supported by the Office of Electricity Delivery and Energy Reliability of the DOE and by the DOE’s Advanced Research Projects Agency-Energy.

With assistance from Harvard’s Office of Technology Development (OTD), the researchers are working with several companies to scale up the technology for industrial applications and to optimize the interactions between the membrane and the electrolyte. Harvard OTD has filed a portfolio of pending patents on innovations in flow battery technology.

ORIGINAL: Daily Accord
Credit: Harvard University
Feb 9, 2017 

The story of the invention that could revolutionize batteries—and maybe American manufacturing as well

This black goop is what will be at the heart of the next generation of batteries.(Kieran Kesner for Quartz)

The world has been clamoring for a super-battery.
Since about 2010, a critical mass of national leaders, policy professionals, scientists, entrepreneurs, thinkers and writers have all but demanded a transformation of the humble lithium-ion cell. Only batteries that can store a lot more energy for a lower price, they have said, will allow for affordable electric cars, cheaper and more widely available electricity, and a reduction in greenhouse gas emissions. In the process, a lot of gazillionaires will be created.

But they have been vexed. Not only has nobody created a super-battery; a large number of researchers have lost faith in their powers to do so—perhaps ever. Entrepreneurs such as Tesla’s Elon Musk continue to tinker with off-the-shelf batteries for luxury electric cars and home power-storage systems, but industry hands seem generally to doubt that their cost will drop enough to attract a mass market any time soon. Increasingly, they are concluding that the primacy of fossil fuels will continue for decades to come, and probably into the next century.

This is where Yet-Ming Chiang enters the picture. A wiry, Taiwanese-American materials-science professor at the Massachusetts Institute of Technology (MIT), Chiang is best known for founding A123, a lithium-ion battery company that had the biggest IPO of 2009. The company ended up filing for bankruptcy in 2012 and selling itself in pieces at firesale prices to Japanese and Chinese rivals. Yet Chiang himself emerged untainted.

In 2010, having rounded up $12.5 million from Boston venture capital firms and federal funds, Chiang launched another company. Again, it was in batteries. And today, after five years in “stealth mode,” he is going public. There may be a way to revolutionize batteries, he says, but right now it is not in the laboratory. There may be a way to revolutionize batteries, but right now it is not in the laboratory. Instead, it’s on the factory floor. Instead, it’s on the factory floor. Ingenious manufacturing, rather than an ingenious leap in battery chemistry, might usher in the new electric age.

When it starts commercial sales in about two years, Chiang says, his company will slash the cost of an entry-level battery plant 10-fold, as well as cut around 30% off the price of the batteries themselves. That’s thanks to a new manufacturing process along with a powerful new cell that adds energy while stripping away cost. Together, he says, they will allow lithium-ion batteries to begin to compete with fossil fuels.

But Chiang’s concept is also about something more than just cheaper, greener power. It’s a model for a new kind of innovation, one that focuses not on new scientific invention, but on new ways of manufacturing. For countries like the US that have lost industries to Asia, this opens the possibility of reinventing the techniques of manufacture. Those that take this path could own that intellectual property—and thus the next manufacturing future.

This is the story of how that came about.

24M batteries.(Kieran Kesner for Quartz.)

Manufacturing, the new frontier of innovation
Traditionally, big innovations have happened at the lab bench. A discovery is made and patented, then is handed off to a commercial player who scales it up. With luck, it turns out a blockbuster product.

But, according to a report published in February by the Brookings Institution, researchers are increasingly skeptical of the delineation between innovation and production. Breakthrough-scale invention, they say, happens not only in the lab, but also in factories.

This is not a new idea. Until 1856, for instance, steel was an ultra-expensive niche product. It was far more robust than iron, but no one knew how to make it economically. Its use was confined to specialty hand tools and eating utensils for the rich. But then British inventor Henry Bessemer, stirred by French gripes about the fragility of cast-iron cannons, devised a process that reduced the cost of steel by more than 80%, roughly equivalent to iron. Steel—along with oil—went on to propel the latter part of the Industrial Revolution, along with the gargantuan 20th century economic boom.

If Bessemer had made his breakthrough today, it would be called “advanced manufacturing”—a label that has been broadly applied to next-generation fabrication methods such as

• 3D printing, 
• modular construction of skyscrapers, and 
• robotics. 

There is some hype around this term: The Brookings report identifies 50 industries in the US alone as “advanced,” and historic factory hubs such as the English city of Sheffield are renaming themselves as variants of “advanced manufacturing cluster.”
Nonetheless, entrepreneurs who develop genuinely novel manufacturing processes can enjoy the advantage of a patent and standing ahead of the crowd. While others will inevitably copy them, it will be a race to catch up. To the degree that such authentic advanced manufacturing moves forward, and can offer the US a chance to reinstate its prowess as a manufacturing hub, it’s led in part by a few clean energy companies like Yet-Ming Chiang’s.

Yet-Ming Chiang, 24M’s founder.(Kieran Kesner for Quartz)

The birth of an idea

At 57, Chiang has short-cropped, gray-flecked black hair, and almost always wears blue, long-sleeved check shirts. He speaks in a soft, even cadence, and is prone to finishing his sentences with a disarming, open-jawed grin.

But if unassuming, Chiang is also tremendously driven. His science-centered business sense has earned tens of millions of dollars for his investors. He and his family live on a farm on the affluent outskirts of Boston, where he raises bees and chickens, and hunts and fishes nearby.