Researchers at the University of Maryland and the University of Houston have developed a sustainable zinc battery with a biodegradable electrolyte made from the same substance as in crab, shrimp and lobster shells. Using rechargeable batteries as green energy sources is key to reducing our reliance on fossil fuels and the emission of greenhouse gases, and here the use of the biomaterial, chitin, is a sustainable approach for green and efficient energy-storage systems.
The global demand for renewable energy and electric vehicles has brought greater need for batteries that can store generated energy and power engines. However, such batteries are not always sustainable and can cause environmental and disposal problems, with some components taking centuries to degrade.
Batteries use an electrolyte, such as a liquid, paste or gel, to move ions between positively and negatively charged terminals. As reported in the journal Matter [Wu et al. Matter (2022) DOI: 10.1016/j.matt.2022.07.015], this new battery, which is able to store power from large-scale wind and solar farms, uses a gel electrolyte made from chitosan, which a derivative product of chitin, which can easily be obtained from seafood waste.
As the electrolyte is biodegradable, around two-thirds of the battery can be broken down by microbes, completely dissolving in soil in less than five months without any treatment, leaving just the metal component, here zinc, which can be recycled. Zinc also has the advantage of being much more abundant on Earth than lithium.
The team examined the performance of the zinc–metal battery with this electrolyte, showing that the cells could operate for 400 hours with an energy efficiency of 99.7% after 1,000 cycles, offering the potential for storing energy generated by wind and solar for transfer to power grids. As well as being biodegradable, the new electrolyte is non-flammable, an important safety factor.
As lead author Liangbing Hu told Materials Today, “we demonstrate the solution can be found to achieve the high performance and biodegradability of material at the same time… We hope this work can attract research community’s attention on the biodegradability of materials when developing new materials for batteries”.
The team now plan to give more consideration to the design of a battery whose components are fully biodegradable, and are hopeful that more and more truly biodegradable batteries will be developed in the future – not only the material itself, but also the fabrication process of biomaterials to help make rechargeable batteries greener and more sustainable.
“We demonstrate the solution can be found to achieve the high performance and biodegradability of material at the same time… We hope this work can attract research community’s attention on the biodegradability of materials when developing new materials for batteries”Liangbing Hu
Biodegradable electrolyte in zinc battery is made from crab shells