By Georgia Barrington-Smith & Dr Rebecca Duncan
With advancements in technology and increases in population leading to a looming energy crisis, it is vital to optimise energy use to meet our future needs. One of the major issues in energy generation is the production of wasted energy in the form of heat. To address this issue of heat loss, we need efficient materials that harness this thermal energy to be used in industries and homes. This practise will enable more efficient energy generation and thereby reduce carbon emissions.
Investigating heat flow in materials
To gain the insights necessary to develop these new materials Caleb Stamper, an AINSE PGRA student, and his collaborators at ANSTO and the University of Wollongong, have investigated the mechanical vibrations of atoms that are responsible for the transport of heat in materials.
Using inelastic neutron scattering techniques combined with structural and thermal property measurements, Caleb was able to explore how heat flows through materials at the atomic scale. Of particular interest to the team were thermoelectric materials, which enable the direct conversion of heat back in to useful electrical energy.
Exploring energy efficient materials
One important consideration for designing heat efficient materials is how well a material retains heat. Materials with low thermal conductivity are ideal, since heat travels slower across such materials, thereby helping them retain heat for longer before expelling it as wasted energy.
Caleb and his collaborators projected that thermoelectric materials could be made more efficient with the addition of carbon nanoparticles, which might significantly lower the material’s heat conductivity. To understand this process, Caleb conducted experiments to investigate the atomic vibrations of pure thermoelectric materials, pure nano-carbon materials, and composite variations. He was able to show that carbon nanocomposites significantly reduce heat conduction, thereby improving the performance of thermoelectric materials.
Exploring energy efficient liquids
As well as investigating solids, the team were also interested in understanding heat transportation in liquids. This poses unique challenges due to liquids having an inherently disordered nature on the atomic scale.
Previously a team of European and Chinese scientists had proposed a theory that could predict the shape of the vibrational density of diverse states of liquids, ranging from hydrogen-bonding small molecular liquids (such as water), liquid metals (such as gallium), and larger, more viscous molecular liquids.
Employing inelastic neutron scattering techniques at ANSTO’s Australian Centre for Neutron Scattering (ACNS), Caleb and his collaborators were able to experimentally confirm this theory, thereby unlocking new information about the thermal properties of complex materials like nanoparticle composites and liquids. These findings will assist in engineering new, more efficient thermal materials that can meet increasing global energy demands.
If you want to be a part of solving the challenges of Australia’s future energy needs, like Caleb, visit ainse.edu.au/scholarships to see how AINSE can support you.
AINSE are proud to spotlight the impressive work of supported students like Caleb.
Read more research spotlights at ainse.edu.au/research-spotlights, and keep an eye out for our December edition, where, in the spirit of the festive season, we will be looking at research done in our polar regions. First off the sled is Dr Rebecca Duncan, who journeys to Santa’s north pole to investigate the effects of climate change on the polar marine food web.
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