(Invited) Heat and Solar Harvesting from Thermoelectric Carbon Nanotube Composites

Abstract

The conversion of waste heat into electricity using solid state devices, namely thermoelectrics, based on carbon materials has experienced renewed interest in the last decade as these materials are particularly suited for large area and low-temperature operation applications since they are abundant, low-toxicity and easy to process [1].In this presentation we will focus on our recent attempts to further extend the sustainability and range of applications of CNT based thermoelectrics. First, we will describe the use bacteria in environmentally friendly aqueous media to grow large area bacterial nanocellulose (BC) films with an embedded highly dispersed CNT network [2]. The thick films are fully bendable, can conformally wrap around heat sources and are stable above 500 K. The resulting composite films exhibit comparable thermoelectric properties to buckypapers while saving more than 90% of the carbon nanotubes. Interestingly, BC can be enzymatically decomposed, thus completely reclaiming the embedded CNTs once the generator has reached the end of its lifetime. Second, we will show our recent studies on the stability of CNT based thermoelectrics, aimed at precisely extending their operational lifetime.Finally, we employ the low thermal conductivities of these composites, granted by the phonon stack-electron tunnel behavior [1], to demonstrate their use as solar thermoelectrics, i.e. materials that convert the energy of the absorbed sun light into heat, and then into electricity [3].[1] Will organic thermoelectrics get hot? M. Campoy-Quiles, Philosophical Transactions of the Royal Society A, 377, 20180352 (2019).[2] Farming thermoelectric paper, D. Abol-Fotouh, B. Dörling, O. Zapata-Arteaga, X. Rodríguez-Martínez, A. Gómez, J. S. Reparaz, A. Laromaine, A. Roig and M. Campoy-Quiles, Energy and Enviromental Science, 12, 716-726 (2019).[3] Solar harvesting: a unique opportunity for organic thermoelectrics? José P. Jurado, B. Dörling, O. Zapata‐Arteaga, A. Roig, A. Mihi and M. Campoy‐Quiles, Advanced Energy Materials, 1902385 (2019). DOI: 10.1002/aenm.20190238