Energy demand is growing and our society faces a challenge to find sustainable sources with minimal environmental impact. Existing technologies such as solar, wind and geothermal have been deployed and effort to improve their physical and cost effectiveness is ongoing. Another source of renewable energy available which has not been harvested to its full potential so far is "waste" heat. It arises from a variety of sources, from household boiler to large scale power plant, and a striking example is the conventional combustion engine in which 60 % of the energy produced is lost in the form of heat. The possibility to design a semiconductor device made of p-n junctions which when exposed to a temperature gradient will output electrical power is an attractive solution for the automotive industry to improve fuel efficiency, lower the carbon foot print and end-user costs. This device, called a thermoelectric generator has been successfully used for aero-spatial application or in its converse form as Peltier cooler, contributes to all component of the energy trilemma. The major barrier for a widespread dissemination of this technology as energy harvester is the high raw material costs and a lack of material for high temperature operation. This research will investigate new classes of inorganic oxide composed of earth abundant elements presenting electrical and thermal properties suitable for integration in a high temperature thermoelectric generator. Efficient thermoelectric materials possess high electrical conductivity and low thermal conductivity which, in a standard semiconductor picture, are antagonistic properties. Focusing on the high temperature spectrum, oxides materials will display the chemical stability required for the device to function reliably. Since the majority of these materials are electrically insulating, the concept is based on identifying structure patterns that have hidden electronic lattice which could act as conducting channel. Similar concept has been successfully applied on layered oxides where only competitive p-type thermoelectric materials where produced. The project aims to explore the possibility to use the strong correlation between electronic, thermal and magnetic lattice to circumvent the limitations encountered in this class of materials and expand our understanding of this complex compounds. A specific objective of the project is to prepare poly- and single crystalline layered oxides derived from the trirutile structure, measure the high temperature conductivity and thermopower and optimise the thermoelectric property using chemical doping to obtain both p and n type compounds. The layered structures of the proposed compounds are conducive to exotic magnetic properties and more complex phenomena such as Nernst-Ettinghausen effect and spin Seebeck effect will be investigated.

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.

The ECOCHAMPS project addresses topic GV-4-2014, Hybrid Light and Heavy Duty Vehicles. The work will, in a single coordinated project, address all aspects of this topic and will be conducted by 26 partners representing the European automotive industry (OEMs (EUCAR), suppliers (CLEPA), ESPs and universities (EARPA)) including members of ERTRAC and EGVIA. The objective is to achieve efficient, compact, low weight, robust and cost effective hybrid powertrains for both passenger cars and commercial vehicles (buses, medium and heavy duty trucks) with increased functionality, improved performance, comfort, safety and emissions below Euro 6 or VI, all proven under real driving conditions. The five demonstrator vehicles, for this purpose developed to TRL 7, that use the hybrid powertrains will among other give a direct cost versus performance comparison at two system voltage levels in the light duty vehicles, and include the modular and standardized framework components in the heavy duty vehicles. Achieving these innovations affordably will strengthen technical leadership in powertrains, enable a leading position in hybrid technology and increases the competitiveness of European OEMs. The vehicles will be ready for market introduction between 2020 and 2022 and (price) competitive to the best in-class (full hybrid) vehicles on the market in 2013. More importantly, the technology devised will impact on the reduction of CO2 emissions and the improvement of air quality. The project proposes to reach a 20% powertrain efficiency improvement and a 20% powertrain weight and volume reduction, with a ≤10% cost premium on the base model for the demonstrator. To meet air quality targets the project will prove, via independently supervised testing, real driving emissions at least below Euro 6 or VI limits and by simulation show the potential of the passenger car technologies to reach Super Low Emission Vehicle standards.