Achievement of extra-high thermoelectric performance in doped copper (I) sulfide

Abstract The development of nontoxic and inexpensive thermoelectric copper (I) sulfide (Cu2S)-based materials could enable an increase in the application of thermoelectric materials in the domain of energy conversion. By using melt quenching, mechanical alloying and spark plasma sintering, we successfully prepared doped and undoped Cu2S with excellent thermoelectric properties. Owing to the increase of carrier concentration, the electrical conductivity of the dopants enhanced from 2.0 × 104 S/m to 1.0 × 105 S/m, with the highest value acquired for Mn doped Cu2S of about 1.0 × 105 S/m at 350 K. Besides, Cu1.8Sn0.1Mn0.1S, Cu1.9Mn0.1S, and Cu1.9Sn0.1S followed an increasing variation in Seebeck coefficient with final values of 325 μV K−1, 322 μV K−1, and 294 μV K−1 at 800 K, respectively. The maximum power factor of 3.24 mW m−1 K−2 is obtained for Cu1.9Mn0.1S at 650 K, which is about 40 times greater than undoped Cu2S (0.08 mW m−1 K−2). At the same time, a peak ZT of 1.63 is attained at 700 K for Cu1.9Mn0.1S, which is about 18 times enhanced over undoped Cu2S (0.09).