As reported by Science Daily, a Bristol-led team has paved the way for more sustainable energy storage with an innovative battery separator made from seaweed.
Combining high-efficiency and low-cost, sodium-metal batteries are widely regarded as one of the most promising avenues for the future of energy storage. However, one major obstacle to the development of sodium-metal batteries is the uncontrolled growth of dendrites - branching crystalline structures produced as molten metal solidifies. As they grow, these dendrites can penetrate the battery's separator, causing it to short-circuit.
According to Jing Wang, first author and PhD student in the Bristol Composites Institute, “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.”
Building on previous work at the University of Bristol, which was undertaken in collaboration with Imperial College and University College London, the team has successfully created a battery separator strong enough to withstand uncontrolled dendrite growth.
The research, published in Advanced Materials, describes how fibres containing cellulose nanomaterials derived from brown seaweed not only stop crystals from the sodium electrodes penetrating the separator, they also improve overall battery performance.
"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," said Wang.
These innovative cellulose nanomaterials were developed by Dr Amaka Onyianta, also from the Bristol Composites Institute, who co-authored the research.