While consumers of crabs know what the core of a crustacean has to offer, scientists are increasingly looking to the animal’s exoskeleton for new medicine and biotechnology.
Much of the interest has centered on chitosan, a derivative of the polysaccharide polymer chitin that is abundant in the shells of crustaceans, as well as insect exoskeletons and fungal cell walls. But scientists have now discovered that upcycling shell casings into hard carbon could become an important part of the electrical circuit for sodium-based rechargeable batteries, a sustainable alternative to current lithium technology.
Researchers have found that producing hard carbon from the shell has the potential to act as an anode in sodium-ion batteries. By heating the shells to temperatures exceeding 1,000°F (538°C), they carbonize the shell and add it to a solution of either tin sulfide (SnS).2) or iron sulfide (FeS2). This forms a viable sodium-ion anode, or positive electrode, in the battery.
Sodium-ion batteries (SIBs) are a new technology and sustainable alternative to lithium-ion batteries (LIBs). Although chemically similar to lithium, the sodium ions are larger and require a different anode than the one typically made of graphite. Here the team of Yun Chen, Yue Zhao, Hongbin Liu and Tingli Ma found a compatible alternative to crabs.
Crab carbon provides a porous, fibrous and large-surface-area anode that improves conductivity and the ability to transport sodium ions. And the team found that in its battery model, the compositions of tin and iron have decent recharging capacities of at least 200 cycles. While it’s not in lithium-battery territory, it’s a positive step toward more sustainable battery technology.
Last year, The World Economic Forum shed light on several issues surrounding the continued viability of mining lithium, predicting potential shortages of the limited resource as early as 2025. The issue is compounded by its impact on the environment, with the high cost of water required in lithium extraction. , with most of the world’s largest mineral sources – Australia, South America – also in drought-prone regions. With its use of EV battery technology fueling massive demand, the race continues to create new sustainable alternatives.
This study comes six months after scientists found that a gel electrolyte derived from chitosan could help power zinc batteries, proving to be more durable and less harmful and flammable. chemicals such as those in current electrolyte solutions that carry the ion-carrying lithium battery.
In the past, chitin and chitosan have played an important role in self-healing paint, biotech transistors, plastic substitutes, flu virus filters and antiviral drugs. On the other hand, scientists are also working hard to find alternatives to the problematic sourcing of Limulus amebocyte lysate (LAL) from horseshoe crab blood, which for more than 40 years has been an important part of the development of safe vaccines and other injectables.
Crab carbon can only be produced from byproducts, which the team sees as having minimal impact on animal populations, in addition to the broader environmental benefits of displacing lithium. While the cost of lithium raw materials is rising, it is also an economical alternative.
“This research provides an efficient route to use cheap waste raw materials to produce high specific energy sodium-ion batteries,” said the authors.
The study was published in the journal ACS Omega.
Source: American Chemical Society
