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Details of Grant 

EPSRC Reference: EP/M50774X/1
Title: GraphTED - graphene nanocomposite materials for thermoelectric devices
Principal Investigator: Freer, Professor R
Other Investigators:
Kinloch, Professor IA
Researcher Co-Investigators:
Project Partners:
Department: Materials
Organisation: University of Manchester, The
Scheme: Technology Programme
Starts: 01 April 2015 Ends: 31 March 2016 Value (£): 99,467
EPSRC Research Topic Classifications:
Materials Processing Materials Synthesis & Growth
EPSRC Industrial Sector Classifications:
Related Grants:
Panel History:  
Summary on Grant Application Form
The Seebeck effect is a thermoelectric effect whereby a temperature gradient across a material is converted to a voltage,

which can be exploited for power generation. The growing concern over fossil fuels and carbon emissions has led to

detailed reviews of all aspects of energy generation and routes to reduce consumption. Thermoelectric (TE) technology,

utilising the direct conversion of waste heat into electric power, has emerged as a serious contender, particular for

automotive and engine related applications. Thermoelectric power modules employ multiple pairs of n-type and p-type TE

materials. Traditional metallic TE materials (such as Bi2Te3 and PbTe), available for 50 years, are not well suited to high

temperature applications since they are prone to vaporization, surface oxidation, and decomposition. In addition many are

toxic. Si-Ge alloys are also well established, with good TE performance at temperatures up to 1200K but the cost per watt

can be up to 10x that of conventional materials. In the last decade oxide thermoelectrics have emerged as promising TE

candidates, particularly perovskites (n-type) and layered cobaltites (e.g. p-type Ca3Co4O9) because of their flexible

structure, high temperature stability and encouraging ZT values, but they are not yet commercially viable. Thus this

investigation is concerned with improving the thermoelectric properties of oxide thermoelectrics, specifically Strontium

Titanate (n-type) and Bismuth Strontium Cobaltite (p-type).

The conversion efficiency of thermoelectric materials is characterised by the figure of merit ZT (where T is temperature); ZT

should be as high as possible. To maximise the Z value requires a high Seebeck coefficient (S), coupled with small thermal

conductivity and high electrical conductivity. In principle electrical conductivity can be adjusted by changes in cation/anion

composition. The greater challenge is to concurrently reduce thermal conductivity. However in oxide ceramics the lattice

conductivity dominates thermal transport since phonons are the main carriers of heat. This affords the basis for a range of

strategies for reducing heat conduction; essentially microstructural engineering to increase phonon scattering. By

introducing small pieces of graphene into the oxide it is possible to produce composites which have reduced thermal

conductivity and increased electrical conductivity. In this way the ZT characteristics of both Strontium Titanate (n-type) and

Bismuth Strontium Cobaltite (p-type) can be enhanced. We will prepare composites of the two oxides, determine their

structures, their phase content and thermoelectric properties. After validation we will construct thermoelectric modules

using the p-type and n-type composites which will be evaluated in commercially-relevant test environments.
Key Findings
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Potential use in non-academic contexts
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Description This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
Date Materialised
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Project URL:  
Further Information:  
Organisation Website: http://www.man.ac.uk