Abstract
Thermoelectrics converting heat and electricity directly attract broad attentions. To enhance the thermoelectric figure of merit, zT, one of the key points is to decouple the carrier-phonon transport. Here, we propose an entropy engineering strategy to realize the carrier-phonon decoupling in the typical SrTiO(3)-based perovskite thermoelectrics. By high-entropy design, the lattice thermal conductivity could be reduced nearly to the amorphous limit, 1.25 W m(-1) K(-1). Simultaneously, entropy engineering can tune the Ti displacement, improving the weighted mobility to 65 cm(2) V(-1) s(-1). Such carrier-phonon decoupling behaviors enable the greatly enhanced μ(W)/κ(L) of ~5.2 × 10(3) cm(3) K J(-1) V(-1). The measured maximum zT of 0.24 at 488 K and the estimated zT of ~0.8 at 1173 K in (Sr(0.2)Ba(0.2)Ca(0.2)Pb(0.2)La(0.2))TiO(3) film are among the best of n-type thermoelectric oxides. These results reveal that the entropy engineering may be a promising strategy to decouple the carrier-phonon transport and achieve higher zT in thermoelectrics.