Published on May 15th, 2017 | by Tina Casey0
3-D Zinc Sponge Could Wipe The Energy Storage Floor With Li-ion Batteries (CleanTechnica Interview)
May 15th, 2017 by Tina Casey
A team of researchers from the Naval Research Laboratory is on to a new zinc-based alternative to lithium-ion batteries. The new research aims at enabling the Navy to expands its energy storage options. The new zinc battery could also makes its way into the EV market, providing manufacturers with a lighter, less expensive alternative to today’s crop of lithium-ion batteries.
Head researcher Debra Rolison, who has been at NRL since 1980, graciously spent some time on the phone last week with CleanTechnica along with her colleague Jeffrey Long to provide some unique insights into the breakthrough.
Yes, EV Batteries Are Safe …
The Navy’s problem with lithium-ion batteries is that they are not considered safe for some applications on ships as well as other facilities due to fire risks.
Don’t get the wrong idea about EV battery safety, though. Modern lithium-ion battery packs are designed with control systems that prevent overheating and provide for a longer lifespan.
Rolison underscored that you’re only going to get safety failure in a poorly designed control system — hoverboards being one notorious example. That kind of problem has practically zero chance of occurring in today’s intensely regulated auto market.
… But They Are Expensive & Heavy
The safety issue does present an obstacle to designing lighter, less expensive energy storage systems, as Rolison explained:
“Lithium-ion thermal management has to be designed in. With other safeguards, these energy management systems add weight, volume, and cost.”
Rolison also noted that thermal management systems add complexity to the manufacturing end of things.
Throw in the additional supply chain complications and you can see why researchers have been pursuing an energy storage system that can safely ditch thermal management systems.
So, Is Zinc The Energy Storage Answer?
Those of you familiar with zinc batteries may be scratching your heads at this point. Though common for single-use batteries, zinc is not the first thing that comes to mind when you’re thinking of rechargeable batteries.
Nevertheless, researchers have been hot on the trail of zinc as an alternative to lithium-ion for a while now.
In addition to the weight and cost advantages, supply chain security is a big consideration. Zinc can be found in many parts of the world and it is abundant in the US. In contrast, lithium mines are few and far between. That could change, eventually, but for the here and now, lithium supply seems like an issue.
“Batteries have to be inexpensive and scalable, and also zinc is not a strategic metal,” Rolison explained. “It can be found anywhere.”
The obstacle is that zinc is a tricky beast as applied to rechargeable batteries. During the charge/discharge cycle, zinc batteries form nanoscale spikes called dendrites that severely limit performance and lifespan.
Researchers have been looking at various solutions — for example, Stanford University has had a zinc-air battery in the works for a while, and just last year Pacific Northwest National Laboratory came up with a zinc-manganese combo for stationary energy storage.
Now, it looks like the Navy is beating them all to the punch.
Zinc Is Not The Answer — But A 3-D Zinc Sponge Is!
The new battery research is a good example of what can happen when researchers persist.
Instead of tinkering around with zinc in its conventional powder form, Rolison’s research team created a nickel-zinc battery that deploys a sponge form of zinc on the anode.
Long provided some historical background:
“There is a whole family of zinc batteries that goes back to [Thomas] Edison’s 1901 patent — in fact, Edison suggested the idea of establishing a naval research laboratory.
“We recognized that the military is comfortable with zinc batteries in their single-use form, and we can re-invent them in rechargeable form. We can apply the zinc sponge across the whole family of batteries.”
The difference between the powder and sponge forms is, well, yuuuuuge according to Rolison:
“The advantages of the sponge form is that zinc is always connected to zinc. We never had that before. That’s why we can oxidize over 90 percent and get almost all of it back. That’s not feasible with powder.”
“We re-imagined zinc for the 21st century,” is how Rolison described the breakthrough.
Here’s a snippet from the team’s study:
“We demonstrate that the three-dimensional (3D) zinc form-factor elevates the performance of nickel–zinc alkaline cells in three fields of use: (i) >90% theoretical depth of discharge (DODZn) in primary (single-use) cells, (ii) >100 high-rate cycles at 40% DODZn at lithium-ion–commensurate specific energy, and (iii) the tens of thousands of power-demanding duty cycles required for start-stop microhybrid vehicles.”
You can find all the details in the journal Science under the somewhat provocative title, “Zinc can compete with lithium.”
As for how long it could take before the new nickel-zinc battery leaps out the laboratory door and lands in your mobile device, that may not take as long as you think.
According to Rolison, the new technology is ready for commercialization and the new batteries can be deployed on a drop-in basis.
That won’t come a moment too soon considering the dustup over the Trump Administration’s actions banning laptops from passenger cabins on aircraft.
For those of you wondering why the Navy has its own research lab, Rolison provided a view of the big picture:
“Energy is all about electrons per second, and that means NRL has a huge charter. NRL is focused on technology the Navy needs, and Navy operations are everywhere — on earth, in space — the Navy’s technology spectrum is everything.
“NRL looks at the technology of the next generation, always trying to understand what lies in the future.”
Women’s History Month has come and gone but in the spirit of recognizing women in STEM fields, here are some snippets from Rolison’s bio:
“Rolison heads the Advanced Electrochemical Materials section at the NRL, where her research focuses on multifunctional nanoarchitectures for such rate -‐‑ critical applications as catalysis, energy storage and conversion, and sensors…
“Rolison is a Fellow of the American Association for the Advancement of Science, the Association for Women in Science , the Materials Research Society (Inaugural Class), and the American Chemical Society and received the 2011 ACS Award in the Chemistry of Materials , the 2011 Hillebrand Prize of the Chemical Society of Washington, and the 2012 C . N. Reilley Award of the Society for Electroanalytical Chemistry…
“When not otherwise bringing the importance of nothing and disorder to materials chemistry, Rolison writes and lectures widely on issues affecting women (and men!) in science, including proposing Title IX assessments of science and engineering departments. She is the author of over 200 article s and holds 24 patents.”
Photo: US Navy damage control exercise by Mass Communication Specialist 3rd Class Arnesia McIntyre.