Innovative syntHEsis and Protection against Aging for Improved Skutterudite-based Thermoelectric generatOrS – I-Hephaistos

Thermoelectric generators convert heat into electricity and thus could help to harvest waste heat released from many industrial processes or empower remote sensors and actuators in extreme environments. Nevertheless, their widespread development is limited by their poor performances and/or their elevated price.

In this context the i-Hephaistos project targets the manufacturing of low-cost and high-power density skutterudite-based thermoelectric modules, by using an energy-efficient process and/or low-cost reactants for the synthesis of the materials, by optimizing the module assembly and by protecting them against oxidation using innovative coatings. The study of the module ageing in operating conditions and the determination of underlying mechanisms will provide valuable guidelines to improve their lifetime.
To reach this goal, five research axes will be developed:
- the up-scaling of the synthesis of pure p- and n-type skutterudites - electrically connected in series and thermally in parallel in the modules - using an energy efficient process recently developed at the Institut des Sciences Chimiques de Rennes (ISCR-1);
- the use of less expensive reactants, mainly of lower grade. The influence of impurities, which should not affect negatively the thermoelectric properties, will be investigated by the Institut de Chimie et des Matériaux Paris-Est (ICMPE);
- the optimization, using simulations, of the thermoelectric performances of the modules followed by their assembly using an innovative one-step process that recently enabled the Institut Jean Lamour (IJL) to reach record-breaking output power densities for skutterudite-based thermoelectric modules;
- the protection against oxidation of these high-power density modules using innovative coatings developed at ISCR-2;
- the investigation of their ageing behaviour at high temperature and upon thermal cycling, simulating operating conditions over long periods of time, will be undertaken by HotBlock OnBoard, a French start-up, national leader in the design and implementation of thermoelectric modules.

The collaboration between 5 partners involved in this project, ISCR-1 (Rennes) for the synthesis of the materials, ICMPE (Thiais) for the fine characterization of the thermoelectric properties, IJL (Nancy) for the modelling and fabrication of the modules, ISCR-2 (Rennes) for the protective coatings, and an industrial partner, HBOB, for ageing tests under operating conditions, gathers all the knowledge and skills required for the successful completion of this ambitious project.
The success of the i-Hephaistos project will lead to low-cost and high-power-density thermoelectric modules with optimized lifetime, in order to prove their applicability to harvest waste heat or empower remote sensors and actuators in extreme environments.