Progress of hybrid nanocomposite materials for thermoelectric applications

Presently, the energy crisis and environmental burden have become two major problems due to the mismanagement of thermal power. Accordingly, the tremendous amount of waste heat from various energy sectors can be utilized by thermoelectric generators as a green energy source. Generally, thermoelectric generators (TEGs) exhibit enormous potential for converting waste heat to electricity without involving any mechanical vibrations and noises. However, they suffer from the disadvantages of expensive manufacturing techniques, low reliability, and scarce availability of conventional thermoelectric materials. Therefore, there has been significant interest from researchers in developing advanced new thermoelectric materials (TEMs). Recently, the promising thermoelectric properties of organic and inorganic nanomaterial-based hybrid nanocomposites have gained popularity among researchers. The grafting of conducting organic and inorganic thermoelectric nanoparticles on graphene/CNT matrices combines the advantages of both inorganic and organic materials. The present review comprehensively presents new hybrid nanocomposite-based TEMs used specifically for wearable TEGs. To demonstrate the performance requirement of these TEGs, we discuss their material synthesis methods, fabrication techniques and possible mechanisms in detail. For comparison, a few traditional TEMs are also reported with the addition of current and potential advanced general applications of TE materials in the form of rigid and wearable devices.