Antimony batteries a possibility
14 Apr 2014 by Evoluted New Media
Scientists probing new materials for batteries have succeeded in producing uniform antimony nanocrystals which could one day be used as alternative anode materials in high-energy-density batteries.
These nanocrystals are able to store large quantities of lithium and sodium ions, the ETH Zurich and EMPA researchers say in Nano Letters, making them suitable for rechargeable batteries. Sodium is of particular interest as a low-cost alternative to lithium.
Antimony has long been regarded as a promising anode material for high-performance lithium-ion batteries thanks to its high charging capacity – a factor of two higher than traditional graphite. However, to achieve these high storage capabilities, it needs to be produced as monodisperse nanocrystals, which researchers have, for the first time, managed to synthesise. The uniform nanocrystals ranged between 10 and 20nm in size.
Full lithiation or sodiation of antimony leads to large volumetric changes; by using nanocrystals these changes in volume can be reversible and fast, and does not lead to the immediate fracture of the material.
In electrochemical tests – led by Maksym Kovalenko – these nanocrystals performed equally well in sodium and lithium ion batteries. The research also enabled the team to identify a size range of 20 to 100nm within which this material shows excellent, size-dependent performance in terms of both energy density and rate capability.
“This greatly simplifies the task of finding an economically viable synthesis method,” Kovalenko said, “Development of such cost-effective synthesis is the next step for us, together with our industrial partner.”
However, Kovalenko is quick to point out that an alternative to lithium-ion batteries is not yet within our grasp. Although the method is relatively straightforward, the production is still too expensive, and he predicts it will be another decade or so before sodium-ion batteries with antimony electrodes could hit the market.
“All in all, batteries with sodium-ions and antimony nanocrystals as anodes will only constitute a highly promising alternative to today’s lithium-ion batteries of the costs of producing the batteries will be comparable.”
Monodisperse Antimony Nanocrystals for High-Rate Li-ion and Na-ion Battery Anodes: Nano versus Bulk
