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Projects: Projects for Investigator
Reference Number	EP/M50774X/1
Title	GraphTED - graphene nanocomposite materials for thermoelectric devices
Status	Completed
Energy Categories	Energy Efficiency(Other) 50%; Other Power and Storage Technologies(Electric power conversion) 50%;
Research Types	Basic and strategic applied research 100%
Science and Technology Fields	PHYSICAL SCIENCES AND MATHEMATICS (Physics) 50%; PHYSICAL SCIENCES AND MATHEMATICS (Metallurgy and Materials) 50%;
UKERC Cross Cutting Characterisation	Not Cross-cutting 100%
Principal Investigator	Prof R (Bob ) Freer No email address given Materials University of Manchester
Award Type	Standard
Funding Source	EPSRC
Start Date	01 April 2015
End Date	31 March 2016
Duration	12 months
Total Grant Value	£99,467
Industrial Sectors	Energy
Region	North West
Programme	Manufacturing : Manufacturing
Investigators	Principal Investigator	Prof R (Bob ) Freer , Materials, University of Manchester (99.999%)
	Other Investigator	Dr IA Kinloch , Materials, University of Manchester (0.001%)
Web Site
Objectives
Abstract	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.
Publications	(none)
Final Report	(none)
Added to Database	20/07/15