Growing high-tech applications for tin

The International Tin Association reports that researchers at the University of Texas at Austin, US have demonstrated that a simple manufacturing route can be used to produce a tin-aluminium alloy that may be cheaper and double the charge capacity of today’s copper-graphite anodes for lithium-ion batteries.

Some 50-70% tin is added to aluminium blocks in the casting process, creating an alloy that can then be mechanically rolled using conventional processes to make a foil. In the process, the tin particles are reduced to nanometer size, trapped inside the aluminium, stabilising them during charging cycles. The resulting material is one quarter as thick and half the weight of typical anodes.

This two-step process is much simpler than the current technology for coating copper electrodes with graphite and doesn’t involve the typical complexities and scalability issues of nanomaterial development. It is also more energy efficient because there is less dilution of the energy capacity usually resulting from the extra weight of a copper backing foil.

This new type of anode material has been named an Interdigitated Eutectic Alloy (IdEA) anode.

“It is exciting to have developed an inexpensive, scalable process for making electrode nanomaterials,” said team leader Arumugam Manthiram, “Our results show that the material succeeds very well on the performance metrics needed to make a commercially viable advance in lithium-ion batteries.”

At the same time the Association reports on liquid tin applications for concentrated solar power plants. A team at Georgia Institute of Technology, US has published advances in its development of liquid tin for use as a heat transfer agent in concentrated solar power (CSP) plants. CSP uses large-scale arrays of reflectors of different kinds to concentrate heat from sunlight onto a heat transfer system, for example in a tower, containing a fluid that can be circulated through a heat turbine to generate electricity.

Tin can operate at higher temperatures than current systems based on molten salts or other fluids, increasing sunlight heat conversion efficiency to around 60%. Switching to tin from molten salts could decrease CSP costs by 30%. Together with partners from other US universities, the Georgia Institute team recently demonstrated suitable containment materials that don’t corrode and developed a ceramic pump that can be used to circulate the tin at up to 1,400°C.

The ITRI view: “CSP costs are economically competitive with fossil fuels in sun-rich regions such as Africa, Australia, South America and the Middle East and some reports suggest that the technology could account for around 10% of global energy supply by 2050.”