Aiming to pave the way for greener and more efficient energy storage, the project builds on previous work at Bristol and is a collaboration with Imperial College and University College London.
Sodium-metal batteries (SMBs) are a promising high-energy and low-cost energy storage system for the next-generation of large-scale applications, researchers said. However, a major impediment to their development is uncontrolled dendrite growth, which penetrate the battery’s separator and result in short circuiting.
Now, according to the team, its separator made from cellulose nanomaterials derived from brown seaweed could solve this challenge.
Published in Advanced Materials, the research describes how fibres containing these seaweed-derived nanomaterials not only stop crystals from the sodium electrodes penetrating the separator, they also improve the batteries’ performance.
“The aim of a separator is to separate the functioning parts of a battery and allow free transport of the charge,” said Jing Wang, first author and PhD student in the Bristol Composites Institute (BCI).
“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.”
Dr Amaka Onyianta, also from the BCI, created the cellulose nanomaterials and co-authored the research. Leader of the research at the BCI, Prof. Steve Eichhorn, said that the results could enhance our capability to move towards sodium-based batteries and reduce reliance on scarce materials such as lithium, which is often mined unethically and uses a great deal of natural resources, such as water, to extract.
“This work really demonstrates that greener forms of energy storage are possible, without being destructive to the environment in their production,” Eichhorn commented.
The team added that the next challenge will be to upscale production of the materials and to supplant current lithium-based technology.