More Than a Fad? Could Zinc-based Batteries Give Li-ion a Run for Its Money?
The search for the next best battery continues into 2022 as companies and researchers look to up-end lithium-ion (Li-ion) technology from its throne. Could zinc be the next contender?
Seemingly every month, we hear about another battery breakthrough that claims to "improve all of humanity."
While many might have their merits, many come and go, proving to be more of an interesting fad than a revolutionary technology.
Overview of a lithium-ion (Li-ion) battery. Screenshot used courtesy of EPA and Argonne
One battery breakthrough that may genuinely have some merit as a revolutionary technology is zinc-based batteries.
In this article, we'll take a look at the technology and the plethora of industry and academic innovations surrounding it.
Zinc-based Batteries
According to many, zinc-based batteries have the potential to serve as a feasible alternative to lithium-ion (Li-ion) batteries.
The layout of a standard zinc-based battery vs. an anode-free battery. Image used courtesy of Zhu et al
Zinc-based batteries work in a very similar fashion to Li-ion batteries.
In these batteries, zinc ions travel from anode to cathode through a liquid electrolyte, and these ions undergo chemical reactions at both the battery's anode and its cathode.
Like lithium-ion, the zinc-ion battery functions using intercalation, which means that, during a discharge cycle, zinc metal from the anode is dissolved into the electrolyte as zinc ions, and these zinc ions get absorbed into the cathode from the electrolyte.
During a charging cycle, the opposite happens.
Now that a bit of a basic understanding of zinc-based batteries has been covered, let's take a look at how this battery technology compares to Li-ion.
Zinc: An Alternative to Lithium?
Zinc batteries are one of many being considered as a solid alternative to lithium batteries for several reasons.
First, and maybe most important, zinc-based batteries are so far the only non-lithium technology that can be manufactured using traditional lithium-ion manufacturing methods.
Secondly, zinc batteries are also highly energy-dense compared to alternatives, allowing for high energy storage in small areas.
Additionally, zinc has the potential to improve on lithium batteries as well.
One reason is that zinc-ion batteries offer improved intrinsic safety over lithium-ion batteries. While lithium-ion batteries are subject to combustion due to a highly combustible electrolyte, zinc batteries use water as an electrolyte, making them significantly safer.
Finally, another reason is that zinc as a raw material is orders of magnitude more abundant than lithium, meaning zinc-based batteries could be cheaper, less harmful for the environment, and less susceptible to supply-chain issues.
Academia Tackles Zinc Batteries
This year saw a significant amount of innovation from academia in the field of zinc-based batteries.
In December of 2021, researchers from Nanyang Technological Innovation in Singapore developed biodegradable, printed paper batteries based on zinc technology.
The batteries were made up of electrodes screen-printed onto both sides of a piece of cellulose paper that has been reinforced with hydrogel.
The results showed that a 4 cm x 4 cm square printed paper battery could power a small electric fan for at least 45 minutes while also being entirely biodegradable.
The researchers hope their new technology will benefit flexible electronic designs in the future.
Example current-voltage curves in the researcher's experiment which used VO2 as a photocathode for zinc-ion batteries. Image used courtesy of Boruah and De Volder
In September of 2021, researchers from the University College of London published a paper on new zinc-based batteries that can be charged directly by light.
The research uses vanadium dioxide (VO2) as a photocathode for zinc-ion batteries.
These batteries leverage zinc oxide as electron transport and hole blocking layer where the VO2 is synthesized.
Overall, this innovation increased photoconversion efficiency while reducing the battery light charging time by 3x.
Industry Innovation
Not only have there been significant innovations for zinc batteries in academia but there has been innovation in the industry as well.
The new ZinCore battery. Image used courtesy of Imprint Energy
Last week, Imprint Energy released a new generation of ultra-thin printed zinc-based batteries.
Coming in at a width of 1.0 mm with a bending diameter of 3 inches, the new ZinCore batteries leverage over ten years of research and 20+ patents to increase energy density while decreasing size.
While many performance specifications are still unknown, the company calls the new generation "the safest and most sustainable battery on the market."
The company hopes to use its new batteries in Internet of Things (IoT) applications with space constraints and support new 5G-based technologies.
The Next Best Battery Material?
Zinc-based batteries are a hot field with many potential applications. This article didn't even scratch the surface of the work going into the zinc battery field.
With so much potential and investment, it seems likely that zinc batteries are more than a fad, but a real technology that can one day give lithium-ion batteries a run for its money.
