Significant enhancement of thermoelectric performance in CoSbS by aliovalent nickel doping
摘要
The natural chalcogenide mineral CoSbS compound has received considerable attention as a promising thermometric material. However, its intrinsically high lattice thermal conductivity and low carrier concentration severely limit the potential applications. Herein, aliovalent Ni-doped CoSbS materials were successfully synthesized using high-energy ball milling and spark plasma sintering. The effects of Ni doping on the electrical and thermal transport properties were systematically investigated. The results revealed that an 8% aliovalent Ni doping dramatically increased the carrier concentration by nearly three orders of magnitude, leading to a remarkable enhancement of two orders of magnitude in electrical conductivity. Additionally, the Seebeck coefficient maintained a relatively high value (approximately − 165 mV K−1 at 900 K) due to the large effective mass and suppressed intrinsic excitation at high temperature. The lattice thermal conductivity decreased substantially due to the strong electron–phonon interaction effect induced by the increased carrier concentration. Consequently, a maximum zT value of 0.56 at 900 K was achieved for the material with 8% aliovalent Ni, representing a 133% increase compared to the pristine CoSbS. This work demonstrates that aliovalent Ni doping is an efficient strategy to improve the thermoelectric performance of CoSbS.