Enhanced Thermoelectric Performance of Rare‐Earth‐Free n‐Type Oxide Perovskite Composite with Graphene Analogous 2D MXene

Abstract Here, the first experimental demonstration on the effect of incorporating new generation 2D material, MXene, on the thermoelectric performance of rare‐earth‐free oxide perovskite is reported. The charge localization phenomenon is predominant in the electron transport of doped SrTiO₃ perovskites, which deters from achieving a higher thermoelectric power factor in these oxides. In this work, it is shown that incorporating Ti₃C₂T_x MXene in a matrix of SrTi_0.85Nb_0.15O₃ (STN) facilitates the delocalization of electrons resulting in better than single‐crystal‐like electron mobility in polycrystalline composites. A 1851% increase in electrical conductivity and a 1000% enhancement in power factor are attained. Besides, anharmonicity caused by MXene in the STN matrix has led to enhanced Umklapp scattering giving rise to lower lattice thermal conductivity. Hence, 700% ZT enhancement is achieved in this composite. Further, a prototype of thermoelectric generator (TEG) using only n‐type STN + MXene is fabricated and a power output of 38 mW is obtained, which is higher than the reported values for oxide TEG.