Concurrently High Thermoelectric and Magnetocaloric Performance of BiSbTe/NiMnIn Composites for All-Solid-State Thermoelectromagnetic Refrigeration

Materials with both high thermoelectric (TE) performance and excellent magnetocaloric (MC) properties near room temperature are of great importance for all-solid-state TE/MC hybrid refrigeration. A combination of such two critical characteristics, however, is hardly attainable in single phase compounds. Herein we report a composite material that comprises Bi-Sb-Te thermoelectric and Ni-Mn-In magnetocaloric components as an innovative thermoelectromagnetic material with dual functionalities. The diffusion mechanism between the two components during solidification is well studied by experimental electron probe microanalyzer tests and theoretical density functional theory calculations. By rationalizing the sintering parameters, the interdiffusion of the two components in the composite material is significantly mitigated. As a consequence, Bi_0.4Sb_1.6Te₃/15 wt % Ni₅₀Mn₃₅In₁₅ composite material demonstrates a high thermoelectric figure of merit (ZT = 0.66) together with a large magnetic entropy change (ΔS_max = 3.08 J kg^-1 K^-1 under a magnetic field of 5 T), both achieved around 300 K. This study suggests that thermoelectromagnetic composite material holds a great promise for all-solid-state TE/MC hybrid cooling.