High-Performance Solid-State Thermal Diode Consisting of Ag2(S,Se,Te)

Abstract

Thermal diodes, in which the magnitude of the heat flow |J| changes with its direction, are a key technology for constructing heat management systems. Composite thermal diodes are composed of two materials possessing opposite temperature dependence of thermal conductivity. Silver chalcogenides Ag2(S,Se,Te) were employed in this work because of their drastic change in thermal conductivity, with a phase transition in the temperature range of 300 K < T < 450 K. A jump of 200% to 500% in their thermal conductivity is observed at the phase-transition temperature, most likely due to the change in electron thermal conductivity. A thermal diode consisting of Ag2S0.6Se0.4 and Ag2S0.1Te0.9, both of which were selected by considering the measured thermal conductivity, has been prepared, and its performance evaluated. The developed thermal diode was confirmed to possess a thermal rectification ratio (TRR) = |Jlarge|/|Jsmall| = 2.7 ± 0.1 when installed between two heat reservoirs kept at TH = 413 K and TL = 300 K. Notably, this TRR is the highest ever reported for a solid-state thermal diode.