Undelaminated multilayer MXenes for block thermoelectric generators

Abstract

MXenes have been garnering significant attention in diverse fields, such as energy storage, catalysis, sensing, and electromagnetic interference shielding. Recently, MXenes were predicted to exhibit excellent thermoelectric properties, and attempts have been conducted to fabricate relevant devices. Nevertheless, the complexity of the preparation process, low productivity, and susceptibility to oxidation have obstructed their full potential. In this study, we investigated the stability of undelaminated multilayers Mo₂TiC₂ and Mo₂C under different conditions, which exhibited a much better thermal stability and oxidation resistance compared to their monolayer counterparts. Moreover, the thermoelectric properties of undelaminated multilayers Mo₂TiC₂ and Mo₂C were studied, which revealed comparable TE performance to monolayer counterparts, with the economy, productivity and stability being greatly improved. Finally, block TE devices with 2 pairs of p/n-type multilayer MXene blocks were prepared in the form of a commercial TE module and generated an open-circuit voltage of 3.43 mV at a temperature difference of 25 K with the maximum output power of 22.68 nW. These results demonstrate a feasible and economical method to process MXene-based thermoelectric devices, opening a new avenue for both MXene and thermoelectric communities.