Generating safe, green energy is one thing but properly storing it for use later on when it is most needed is crucial to creating a completely sustainable energy supply. Finding suitable energy storage solutions saves surplus energy from becoming waste and has a positive environmental impact by generating a cleaner, greener energy supply.

Batteries are amongst the most common energy storage solutions, but they are also the limiting factor when it comes to the transition to greener energy sources. One of the recurring issues regarding sodium-based batteries is the growth of dendrites. These tentacle-like microstructures typically form as the battery goes through charging cycles.

Dendrites can be dangerous to a battery’s health as they can pierce the separator membrane between the two electrodes and cause short circuits, which can potentially result in fires.

Recently, a group of researchers based in Bristol have developed nanomaterials that incorporate seaweed into their makeup to produce a robust battery separator. Published in the journal Advanced Materials, the separators could herald a new wave of greener and more efficient energy storage devices.

Sodium-Metal Batteries

Recently, sodium-metal batteries (SMBs) are attracting a lot of attention as sodium-ion chemistry offers a more environmentally compatible approach than using traditional materials such as lithium-ion. While lithium is the most commonly used metal in present battery technology, due to its rapid charging capabilities and high power density, it is expensive to mine due to its relative scarcity, and lithium extraction can be detrimental to the environment.

However, sodium is a much more abundant material and also offers relatively high power density and theoretical capacity. The researchers from the University of Bristol believe that improving the components of this technology could give SMBs a key role in the future of energy storage.

To develop an innovative new separator using brown seaweed, the Bristol-led team collaborated with researchers at University College London (UCL) and Imperial College London. The separator uses cellulose nanomaterials which have the theoretical ability to stop crystals and dendrites from forming and penetrating the separator; they also enhance overall battery performance.

Greener, Greater Energy Storage

The work between the teams demonstrates that making energy storage solutions environmentally compatible and greener for a sustainable energy supply in the future is, in theory, possible. Moreover, by improving the capacity and efficiency properties of SMBs, the team hopes it will improve the longevity of the batteries too.

The team demonstrated in their work that the batteries that included seaweed-based cellulose nanomaterials could sustain high energy density when subjected to more than 1000 cycles. This unprecedented achievement in battery stability means that the approach has the potential to be used in other battery types.

With lithium-ion batteries being the most relied upon in everything from smartphones to electronic vehicle batteries, the team hopes that their novel nanomaterials could usurp the dependency on li-ion energy storage technology. The next steps are finding ways to upscale the production of seaweed-derived energy storage solutions to create a more sustainable energy system in the near future.