Nanostructured Thermoelectric Oxides for Energy Generation: A Combined Experimental and Modelling Investigation

Lead Research Organisation: University of Manchester
Department Name: Materials

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 (such as n-type CaMnO3) 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 understanding and improving the thermoelectric properties of oxide materials based on CaMnO3 and ZnO. Furthermore, not only do they represent very promising n-type materials in their own right but by using them as model materials with different and well-characterised structures we aim to use them to identify quantitatively how different factors control thermoelectric properties.
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 at the nanoscale to increase phonon scattering. The nanostructuring approaches will be: (i) introduction of foreign ions into the lattice, (ii) development of superlattice structures, (iii) nanocompositing by introducing texture or nm size features (iv) development of controlled porosity of different size and architecture, all providing additional scattering centres. Independently, TE enhancement can also be achieved by substitution of dopants to adjust the electrical conductivity. By systematically investigating the effect of nanostructuring in CaMnO3 and ZnO ceramics, plus the development of self-assembly nanostructures we will be able to define the relative importance of the factors and understand the mechanisms controlling thermal and electron transport in thermoelectric oxides.
A key feature of the work is that we will adopt an integrated approach, combining advanced experimental and modelling techniques to investigate the effect of nanostructured features on the properties of important thermoelectric oxide. The modelling studies will both guide the experimentalists and provide quantitative insight into the controlling mechanisms and processes occurring at the atom level to the grain level, while the experiments will provide a rigorous test of the calculation of the different thermoelectric properties.
We will assess the mechanical performance of optimised n-type and p-type materials, and then construct thermoelectric modules which will be evaluated in automobile test environments.

Planned Impact

The work will provide a foundation for the development and exploitation of high temperature thermoelectric ceramics to generate energy via waste heat. The beneficiaries in the commercial sector are threefold: (i) ceramic manufacturers who will have new products, (ii) producers of energy management devices who will be able to develop new products for new high temperature markets, and (iii) users of thermoelectric modules, such as motor manufacturers, generating energy from waste heat. Policy makes will benefit from the research by knowledge of developments of environmentally friendly methods of energy generation and a way to help reduce the use of fossil fuels.
There will be opportunities for museums with exhibits highlighting the principles of thermoelectric power generation and applications from automobiles to domestic environments. To the wider public there will be environmental benefits of utilising oxides in place toxic metal thermoelectrics and from the generation of energy from waste heat, leading to improved fuel consumption for automobiles and economic benefit to individuals and the UK.
The research has the potential to impact the wealth and the economic competitiveness of the UK by the development of enhanced thermoelectric materials and power modules. For UK companies there will be new opportunities and new markets in the production of ceramics, the development of energy management systems, and exploitation of energy generation systems. All companies in the supply chain should become more competitive. With generation of power from waste heat in the automobile and other sectors there will be improved fuel consumption and the potential for reduction of imported oil to the UK, giving additional economic benefits. New thermoelectric power modules should be realised within 3-5 years, bringing benefits to companies in the supply chain within 3-7 years. The wider benefits of effective power generation and potential reduction of oil consumption should come within 5-10 years.
The researchers working on the project will gain transferable skills in materials fabrication, microstructural and functional property characterisation, advanced modelling techniques together with skills in report writing and critical analysis that will be of value in future employment.
We will establish a network linking UK industrial companies relevant to the supply chain, users of power generation modules, plus other academics in the field. Regular contact and news of developments will be circulated via electronic newsletters and a Workshop will be held in year 3 of the project. Non-confidential findings will be published on a project web page. Scientific and technological findings will be disseminated to the academic and industrial communities via presentations at major international conferences and high impact refereed publications.
Our industrial collaborators cover all aspects of the supply chain: Morgan Electroceramics (ceramic producer), ETL (Energy Management), Ricardo (engine designer), Jaguar (vehicle manufacturer) and Rolls Royce (engine manufacturers). Our academic collaborators provide additional expertise: P Colombo (Padova) routes to controlled porosity, M Reece (QMUL) SPS techniques, A Wiedenkaff (EMPA) single crystal growth, J-F Li (Tsinghua) p-type materials. With collaborators we will protect and exploit IP through the University of Manchester Technology Transfer Unit and University of Bath Research Development and Collaborations Unit. The Manchester applicants (RF, CAL) have over twenty years experience of investigating structure-property relationships in electroceramics, including thermoelectric materials; the Bath applicant (SCP) has over thirty years experience of developing and using high level computer codes to investigate the role of phonons, structure and stability of oxides. With academic and industrial collaborators we have the necessary expertise and facilities to successfully undertake the programme of work.

Publications

10 25 50

 
Description Improved understanding of combined expeimental and modelling investigations of oxide thermoelectrics
Exploitation Route Development of new oxide thermoelectric materials and composites for power generation
Sectors Chemicals,Electronics,Energy,Manufacturing, including Industrial Biotechology,Transport

 
Description being used in follow up projects on oxide thermoelectrics to estiblish greater understanding of controlling mechanisms
First Year Of Impact 2012
Sector Energy,Manufacturing, including Industrial Biotechology,Transport
Impact Types Economic

 
Description MISE Functional Materials Network
Amount £30,000 (GBP)
Organisation University of St Andrews 
Sector Academic/University
Country United Kingdom
Start 05/2018 
End 08/2018
 
Description Realising the Graphene potential
Amount £99,000 (GBP)
Funding ID EP/M50774X/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 04/2015 
End 03/2016
 
Description UMIP
Amount £180,000 (GBP)
Organisation University of Manchester 
Sector Academic/University
Country United Kingdom
Start 11/2018 
End 02/2020
 
Description Queen Mary 
Organisation Queen Mary University of London
Country United Kingdom 
Sector Academic/University 
PI Contribution Development of Oxide thermoelectrics; electron microscopy
Collaborator Contribution Processing of thermoelectric oxides
Impact publications
Start Year 2008
 
Description SuperSTEM 
Organisation Daresbury Laboratory
Country United Kingdom 
Sector Private 
PI Contribution Development of novel thermoelectrics
Collaborator Contribution Atom level electron microscopy
Impact publications
Start Year 2009
 
Description ACerS MCARE Conference Vancouver Canada August 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact ACerS MCARE International Conference on Energy Materials; 700 delegates
Year(s) Of Engagement Activity 2018
 
Description Annual MASSIVE Research Workshop on Environmetally Friendly Energy Materials - Weston Super Mere UK 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Annual MASSIVE Research Workshop on Environmetally Friendly Energy Materials - 80 peolple attended; research presentations over two days; invited talks from industry.
Year(s) Of Engagement Activity 2018
 
Description CLOSELOOP Energy Materials Workshop, Helsinki Finland November 2018 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact CLOSELOOP Energy Materials Workshop, concerned with environmentally friendly materials, 75 delegates
Year(s) Of Engagement Activity 2018
 
Description Energy Materials Network Workshop, Edinburgh, UK 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact One day international research workshop reviewing developments in energy materials and their applications
Year(s) Of Engagement Activity 2017
 
Description European Microscopy Conference, Lyon 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presented talk - Recent applications of high energy and spatial resolution STEM-EELS to energy harvesting materials
Year(s) Of Engagement Activity 2016
 
Description European Microscopy Conference, Lyon 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact talk reporting - Mapping cation-vacancy ordering and oxygen octahedral distortions in A-site deficient perovskites by monochromated core-loss EELS
Year(s) Of Engagement Activity 2016
 
Description European Thermoelectric Conference lLisbon 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk - Effect of sintering aids and annealing time on the thermoelectric properties of Sr0.61Ba0.39Nb2O6-d.
Year(s) Of Engagement Activity 2016
 
Description European Thermoelectric Conference lLisbon 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk reporting - Crystal Structure and High Temperature Thermoelectric Properties of La1/3NbO3 Perovskite
Year(s) Of Engagement Activity 2016
 
Description European Thermoelectric Conference lLisbon 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk on - The effect of stoichiometry on the crystal structure and thermoelectric properties of Bi2+xSr2Co2Oy
Year(s) Of Engagement Activity 2016
 
Description India-UK Thermoelectric Workshop, India Bangalore 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Thre day international research workshop reviewing developments in thermoelectric materials and their applications. Explored possible bids for international collaboration
Year(s) Of Engagement Activity 2018
 
Description International Conference on Thermoelectrics, Caen France July 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact International conference thermoelectrics; 600 delegates, presentations over 5 days.
Year(s) Of Engagement Activity 2018
 
Description International Thermoelectric Symposium, Dresden 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk reporting - Tungsten Bronze Barium Neodymium Titanate (Ba6-3xNd8+2xTi18O54): A new high temperature oxide thermoelectric
Year(s) Of Engagement Activity 2015
 
Description MISE Functional Materials workshop Birmingham UK 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact MISE Functional Materials workshop; 70 delegates
Year(s) Of Engagement Activity 2018
 
Description Materials Research Society Annual Meeting Arizona 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk reporting - Thermoelectric Graphene-Strontium Titanate composites with High ZT and Wide Operating window - to international research audience
Year(s) Of Engagement Activity 2016
 
Description Novel Energy Materials Workshop - lLverpool UK 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Series of presentations on Novel Energy Materials - 60 people attended; Liverpool University
Year(s) Of Engagement Activity 2018
 
Description PacRim International Conference Hawaii USA 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact PacRim International Conference Hawaii USA; session concerned with energy materials
Year(s) Of Engagement Activity 2017
 
Description Royal Society Discussion Meeting on Energy Materials Buckinhamshire UK 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Royal Society Discussion Meeting on Energy Materials; 80 delegates
Year(s) Of Engagement Activity 2018
 
Description Thermoelectric Materials Symposium Japan 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk reporting - High ZT Graphene-Strontium Titanate Thermoelectric Composites - to international audience
Year(s) Of Engagement Activity 2015
 
Description Thermoelectric Network Meeting in Edinburgh UK 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact One day workshop on thermoelectric energy materials and devices - EPSRC Thermoelectric Network
Year(s) Of Engagement Activity 2018
 
Description Thermoelectric Network Workshop, Edinburgh, UK 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact One day international research workshop reviewing developments in thermoelectric materials and their applications
Year(s) Of Engagement Activity 2018
URL http://www.thermoelectricnetwork.com/home.html
 
Description Thermoelectric Network Workshop, Glasgow UK 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact One day workshop on progress in thermoelectric materials and their applications
Year(s) Of Engagement Activity 2016
URL http://www.thermoelectricnetwork.com/home.html
 
Description Thermoelectric Network Workshop, Manchester, UK 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Two day international research workshop reviewing developments in thermoelectric materials and their applications
Year(s) Of Engagement Activity 2017
URL http://www.thermoelectricnetwork.com/home.html
 
Description Thermoelectric Network Workshop, Manchester, UK 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Series of presentations by specialist on thermoelectrics defining the status of the field and needs for future development
Year(s) Of Engagement Activity 2014
URL http://www.thermoelectricnetwork.com/home.html
 
Description Thermoelectric Network Workshop, NPL Teddington, UK 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact One day workshop on research developments in thermoelectrics, and one day training event on measurement techniques for thermoelectrics
Year(s) Of Engagement Activity 2016
URL http://www.thermoelectricnetwork.com/home.html
 
Description Thermoelectric Network Workshop, Reading UK 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Study participants or study members
Results and Impact One day workshop on techniques and applications in thermoelectrics, followed by one day Trainng Event for younger workers - theme of modelling in Thermoelectrcs
Year(s) Of Engagement Activity 2015
 
Description Thermoelectric Network Workshop, Southamton, UK 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact One day international research workshop reviewing developments in thermoelectric materials and their applications
Year(s) Of Engagement Activity 2017
 
Description Thermoelectric Network Workshop, loughborough UK 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Series of presentations by specialist on thermoelectrics concerned with engineering applications. Training event for postgraduate students and young researchers concerned with use of thermoelectrics for automotive applications
Year(s) Of Engagement Activity 2015
URL http://www.thermoelectricnetwork.com/home.html