“…They directly convert waste heat into electricity based on the Seebeck effect [1][2][3]. The performance of thermoelectric materials was evaluated using the dimensionless thermoelectric figure of merit, zT = σS 2 T/ κ elec + κ latt , where σ, S, T, κ elec , and κ latt denote the electrical conductivity, Seebeck coefficient, absolute temperature, electronic thermal conductivity, and lattice thermal conductivity, respectively [4,5]. To achieve a high zT value, increased σ and S and decreased total thermal conductivity κ tot , which are the sum of κ elec and κ latt , are required.…”