Toward Ultrahigh Thermoelectric Performance of Cu2SnS3-Based Materials by Analog Alloying

Cu2SnS3 is a promising thermoelectric candidate for power generation at medium temperature due to its low-cost and environmental-benign features. However, the high electrical resistivity due to low hole concentration severely restricts its final thermoelectric performance. Here, analog alloying with CuInSe2 is first adopted to optimize the electrical resistivity by promoting the formation of Sn vacancies and the precipitation of In, and optimize lattice thermal conductivity through the formation of stacking faults and nanotwins. Such analog alloying enables a greatly enhanced power factor of 8.03 mu W cm(-1) K-2 and a largely reduced lattice thermal conductivity of 0.38 W m(-1) K-1 for Cu2SnS3 - 9 mol.% CuInSe2. Eventually, a peak ZT as high as 1.14 at 773 K is achieved for Cu2SnS3 - 9 mol.% CuInSe2, which is one of the highest ZT among the researches on Cu2SnS3-based thermoelectric materials. The work implies analog alloying with CuInSe2 is a very effective route to unleash superior thermoelectric performance of Cu2SnS3.

Automated summary

Cu2SnS3 is a promising thermoelectric material for medium-temperature power generation with low-cost and environmental-benign features. Analog alloying with CuInSe2 is adopted to optimize its electrical resistivity and lattice thermal conductivity, resulting in greatly enhanced power factor and reduced lattice thermal conductivity. A peak ZT value of 1.14 at 773 K is achieved for Cu2SnS3 - 9 mol.% CuInSe2, which is one of the highest among Cu2SnS3-based thermoelectric materials. The study demonstrates that analog alloying with CuInSe2 is an effective route to unleash superior thermoelectric performance of Cu2SnS3.