Electronic thermoelectrics use semiconductors to convert waste heat into electricity. This is an established energy generation technology, for example, used by NASA to power the Mars Rovers. However, it is not very suitable for low-grade waste heat recovery due to poor power generation from small temperature differences. Ionic conductors generate much larger thermal voltages and are better suited to near room temperature operation. However, they cannot be used in the same mode of operation as this would require a continuous flow of ions. The innovative solution proposed is to couple the ionic conductor with an energy storage system that converts the ionic potential to an electronic one. This proposal will investigate novel ionic thermoelectric power generation devices consisting of an ionic conductor sandwiched between two energy stores, including supercapacitors and insertion materials. This is a novel approach targeted at recovery of low-grade waste heat, increasing the sustainability of industrial processes and reducing carbon emissions.

Application of the Spin-Seebeck-Effect (SSE), only demonstrated in 2008/10, potentially allows new types of large area single layer thermoelectric (TE) devices for heat-energy exchange (waste heat energy recovery or micro Peltier cooling) under near ambient temperature applications. Present SSE research demonstrations (based on synthetic garnets coated with Pt) are unsuited and unsustainable for real-World application. We proposed two new ways to attain more sustainable, lower cost SSE devices: (i) Use of a facilitating organic interface between the SSE and metal layers to facilitate spin transfer out of the SSE layer; (ii) replacement of the Pt metal layer by more sustainable metals.

Thermoelectric devices are devices that use electricity to pump heat. They can provide both heating and cooling in the same device. Their lack of moving parts makes them good choices for robust, small, quiet, environmentally friendly systems with minimal maintenance. Existing thermoelectric systems are rigid, and more complex shapes or softer surfaces such as the body are difficult to interact with. Our proposal, entitled FlexiTEC, is to develop a fully flexible thermoelectric system. This will increase the ease of use of thermoelectric systems, and encourage take up in personal thermoelectric temperature control systems, for example in active heating and cooling seating products. Such local environment control can significantly save energy, as only the environment that you immediately feel is controlled, rather than the entire space around you. In addition thermoelectric systems have a higher efficiency in heating then local electrical heaters. These efficiency advantages are especially important in electric vehicle development, where cabin temperature control can have up to a 40% impact on range for example in freezing conditions. In order to achieve this aim, full system level modelling and optimisation of the coupled impact of thermoelectric materials, device architecture and flexible heat sinks will be performed in order to achieve the required balance between electrical, thermal and mechanical properties. This will direct the material, device and system innovation in order to accelerate progress towards a high performance, robust, flexible system. Development work will include novel processing routes to enable next generation miniaturisation, coupled with a module designed to be more resistant to failure than conventional devices. In addition, flexible heat sinks will be optimised and constructed using novel low cost processing. This work will be undertaken at European Thermodynamics Ltd near Leicester, a leading UK centre for industrial thermoelectrics research, and will partner with University of Leicester and Queen Mary University of London to harness their expertise in the mechanics of thermoelectric materials and advanced thermoelectric processing routes respectively.

Thermoelectric materials convert waste heat into useful electric power. Even inefficient thermoelectric power generation recovery can have a substantial impact on UK and global energy consumption because more than half of primary energy is ultimately wasted as heat. So far, thermoelectric generators (TEGs) have been restricted to niche applications, such as powering the Voyager space probes, where durable, reliable and low-maintenance power generation is essential. However, the market for thermoelectric energy harvesters is projected to approach $1bn within a decade.* Potential applications for TEGs include scavenging heat from car exhausts, producing combined heat and power units for use in remote, off-grid locations, and replacing batteries in wearable microelectronic devices. A major limitation has been to develop cheap, efficient TEGs that do not rely on toxic or scarce resources. For example, the most efficient thermoelectric material for automobile heat recovery is currently a compound of toxic lead and scarce tellurium. In this project, we aim to develop a viable, non-toxic alternative to lead telluride TEGs, using 'Heusler alloys', which combine abundant elements such as titanium, nickel and tin. They also meet the majority of industrial requirements for thermoelectric power generation, having good thermal and mechanical stability, mechanical strength and ease of processing. However, a TEG's thermal conductivity is also critical and optimising the thermal conductivity of Heusler alloys has been problematic. We aim to capitalise on our recent advances in Heusler alloy synthesis and nanostructuring, which currently represents the only UK efforts in this fast-growing field. The ultimate aim of this proposal is to develop new means of controlling the thermal conductivity of Heusler alloys in order to build a TEG prototype of comparable performance to existing lead telluride devices. Our insight is that there are a variety of alloy phases and intentional defects that can be used to introduce structural texture on the nanoscale, thereby reducing the thermal conductivity. What is exciting is that many of these structures have not previously been studied. A critical aspect is the size and distribution of the texturing, which should be long enough to avoid reducing the material's electrical conductivity but short enough to impede the flow of heat. We will investigate the optimum length-scales for texturing by performing a systematic study of the impact of processing conditions on the HA nanoscale structure. We will use world-leading electron microscopy, neutron scattering facilities and theoretical modelling to probe the atomic-scale structure and dynamics of the new materials in order to optimise the synthesis parameters. We will then use this technical know-how in collaboration with our industrial partner European Thermodynamics Ltd. to build prototype TEG modules. This collaborative project, involving three academic institutions, national facilities and a UK small business, has substantial potential for impact, with notable prospects for making a contribution to lowering the UK's carbon footprint. It also provides excellent opportunities for knowledge transfer to a vibrant new industry and for high-quality training. * H. Zervos, "Thermoelectric Energy Harvesting 2014-2024: Devices, Applications, Opportunities," 2014

The Seebeck and Peltier effects are thermoelectric effects which occur particularly strongly in semiconductors whereby a temperature gradient across a material is converted to a current which can be exploited for power generation, or the use of an externally supplied electrical current to cause a flow of heat in the material. The growing concern over fossil fuels and carbon emissions has led to detailed reviews of all aspects of energy generation, transportation and routes to reduce consumption. Thermoelectric (TE) technology, utilising the direct conversion of waste heat into electric power or vice versa has emerged as a serious contender, particularly for self-powered sensors, automotive and heat engine related applications. Thermoelectric power modules employ multiple pairs of n-type and p-type TE materials arranged electrically in series and thermally in parallel and formed into ceramic modules of usually less than 60mm x 60mm. In an effort to enhance the UK's capability in this key area, we propose to establish a network in TE materials, device physics and systems. The network will serve as a focal point for activity and bring together workers in different disciplines to define and address the considerable research challenges presented in realising the potential offered by this technology. The initial membership of the Network will include 13 universities (representing Physics, Chemistry, Materials and Engineering disciplines), The National Physical Laboratory, 7 industrial partners covering all aspects of the Thermoelectric module design and manufacture supply chain, plus a large number of end users. In total over 32 individual organisations will be represented. With a broad based interdisciplinary partnership we will adopt an integrated approach addressing: (i) Theory - to understand the factors controlling thermoelectric properties and ways to predict properties on the basis of structure and composition. (ii) Investigations of structure - at both atomic levels and microstructure levels to underpin theoretical studies and support processing-structure-properties studies. (iii) Materials and device processing - to identify ways of improving materials and devices (iv) Property Measurements - validation of measurement techniques (v) Simulation and modelling of device and system performance (vi) Interfaces and interconnects - understanding the problems limiting performance (vii) Systems electronics- identification of architectures appropriate to different applications; (viii) Applications and Markets - identifying needs and the devices/systems required. A management committee will be established to co-ordinate the activities of the Network and to monitor the scientific and technical programmes. The management committee will: (i) organise at least two meetings per year and an annual workshop; (ii) help with defining themes for collaborative programmes; (iii) assist with the exchange of students/workers; (iv) establish links with national and international organisations. A secretary/administrator will support day to day running of the Network, and be responsible for communication via a web page and newsletters. The Network will provide increased opportunities for joint projects, inter-laboratory measurement comparisons, the definition of a Roadmap for Thermoelectrics, and the initiation of novel research programmes.