Polymer-based thermoelectric materials

The thermoelectric effect is a physical phenomenon that converts an electrical potential difference into a temperature difference (Peltier effect), or conversely, a temperature difference into an electrical potential difference (Seebeck effect). In addition to exploiting thermoelectricity for applications in the fields of thermometry or refrigeration, thermoelectric devices are of obvious interest for recovering heat released or lost on exothermic installations. The current economic and environmental contexts, characterized on the one hand by the depletion of natural fossil energy sources and on the other by the quest for alternative, more environmentally-friendly energy sources, represent an ideal framework for the development of devices of this kind.

Advances in the synthesis of new materials adaptable to thermoelectric systems with complex geometries and capable of exploiting small temperature differences could make it possible, for example, to recover human heat or the heat from portable devices used on a daily basis, offering virtually unlimited potential for energy recovery.

The performance of a thermoelectric material, in terms of energy conversion efficiency, is characterized by a dimensionless parameter noted zT (or ZT) and called the "thermoelectric factor of merit" [N 1 500][K 730][BE 8 080] . This is the product of the electrical conductivity σ and the square of the Seebeck coefficient S divided by the thermal conductivity κ. To maximize the zT parameter (and therefore energy conversion efficiency), the material under consideration must have both a high electrical conductivity (in the case of metals) and a high Seebeck coefficient, while also being a good thermal insulator (in the case of insulators). The thermoelectric effect is observable in most conducting materials (except for superconductors below T _c ), but the figure of merit is optimal for charge carrier...