According to research, scientists want to use a chemical found in crab and lobster shells to make batteries last longer.
“We believe that material biodegradability, or environmental impact, and battery performance are important for a product, which has the potential to be commercialized,” said Liangbing Hu, director of the Center for Materials Innovation at the University of Maryland and leader. author of the article, published in the journal Matter.
As the world moves towards the deployment of green energy solutions and electric vehicles, the batteries used for this technology must also be environmentally friendly.
But the chemicals used in conventional batteries such as lithium-ion can take hundreds or thousands of years to break down. These chemicals are also often corrosive and flammable. In some cases, batteries from consumer gadgets have caught fire in airplanes or caused fires at waste and recycling sites.
Maryland researchers have developed batteries that use a product derived from crustacean shells to store energy.
Crustaceans like crabs, shrimps, and lobsters have exoskeletons made up of cells that contain chitin, a kind of polysaccharide that makes their shell hard and tough. This valuable material is abundant in nature and can also be found in fungi and insects, but is commonly discarded as food waste from restaurants and as a by-product of the food industry. Scientists have long studied its various applications – in biomedical engineering, for example, for wound dressing as well as anti-inflammatory treatments – and now, in electrical engineering.
Through chemical treatment and the addition of an aqueous solution of acetic acid, chitin can finally be synthesized into a firm gel membrane and used as an electrolyte for a battery. An electrolyte is the liquid, paste, or gel inside a battery that helps ions – charged molecules – move from one end of a battery to the other, allowing it to store energy. ‘energy.
By combining this chitosan electrolyte with zinc, a natural metal increasingly used to make cheap and safe batteries, Hu’s team was able to create a renewable battery.
The battery has an energy efficiency of 99.7% even after 1000 battery cycles, or approximately 400 hours. This means that they can be quickly loaded and unloaded without significantly affecting their performance. “It is not an easy thing for batteries to operate at high current density. The displayed performance suggests the merit of the chitosan material in this work,” Hu said.
The batteries are non-flammable and two-thirds of the chitosan battery can decompose in the ground through microbial degradation in just five months, leaving behind recyclable zinc. Antonio J Fernández Romero, professor of materials science for energy production at the University of Cartagena in Spain, who was not involved in the study, said these were “exceptional properties”.
He said: “The design of new environmentally friendly batteries that are inexpensive and produce high discharge capacity is one of the most important things to be developed in the years to come.” He added that biodegradability was essential and that at this level the system seemed to work very well, but it would need to be tested on a larger scale and under commercial use conditions.
The design could pave the way for the development of high-performance, long-lasting batteries for green energy storage, according to Hu and the study authors.
“When you’re developing new materials for battery technologies, there’s usually a big gap between promising lab results and demonstrable, scalable technology,” said Graham Newton, professor of materials chemistry at the University of Nottingham. , who did not participate in the study. . He is an expert in sustainable batteries and researches how they can be improved.
So far, according to Newton, the results of chitosan-zinc batteries are promising. “There are examples of batteries like this that have been commercialized and are being tested as stationary energy storage systems,” Newton said. “There are still quite a few challenges in the development of zinc-ion batteries, but fundamental studies like this are extremely important.”