A team led by Bristol is building a sturdy battery separator with seaweed-derived nanomaterials, paving the way for cleaner and more efficient energy storage.
One of the most promising high-energy and affordable energy storage solutions for the upcoming wave of large-scale applications is sodium-metal batteries (SMBs). However, uncontrolled dendrite formation, which penetrates the battery’s separator and causes short-circuiting, is one of the main barriers to developing SMBs.
The team has successfully created a separator out of cellulose nanoparticles generated from brown seaweed, building on earlier work at the University of Bristol and collaborating with Imperial College and University College London.
The study, published in Advanced Materials, explains how fibers containing these seaweed-derived nanomaterials prevent sodium electrode crystals from accessing the separator and improve battery performance.
The aim of a separator is to separate the functioning parts of a battery (the plus and the minus ends) and allow free transport of the charge. We have shown that seaweed-based materials can make the separator very strong and prevent it being punctured by metal structures made from sodium. It also allows for greater storage capacity and efficiency, increasing the lifetime of the batteries—something which is key to powering devices such as mobile phones for much longer.
Jing Wang, Study First Author and PhD Student, Bristol Composites Institute, University of Bristol
The study’s co-author and the developer of the cellulose nanomaterials, Dr Amaka Onyianta of the BCI stated, “I was delighted to see that these nanomaterials are able to strengthen the separator materials and enhance our capability to move towards sodium-based batteries. This means we wouldn’t have to rely on scarce materials such as lithium, which is often mined unethically and uses a great deal of natural resources, such as water, to extract it.”
Professor Steve Eichhorn, the study’s lead researcher at the Bristol Composites Institute, remarked, “This work really demonstrates that greener forms of energy storage are possible, without being destructive to the environment in their production.”
The subsequent challenge is to scale up the production of these materials and replace existing lithium-based technology.
Wang, J., et al. (2022) Stable Sodium Metal Batteries in Carbonate Electrolytes Achieved by Bifunctional, Sustainable Separators with Tailored Alignment. Advanced Materials. doi:10.1002/adma.202206367.