Boosting carrier mobility in MgAgSb via in-situ InSb nanoprecipitates for high-efficiency segmented thermoelectric module

Carrier mobility has conventionally been manipulated to enhance thermoelectric performance by reducing crystal defects. Therefore, an effective strategy for optimizing carrier mobility is highly desired for nanostructured materials. In this work, InSb nanoprecipitates are formed in situ within the nanostructured MgAgSb matrix, serving as channels for accelerating charge carriers. A high carrier mobility of 93.1 cm²V^-1 s^-1 is achieved in MgAg_0.97Sb_0.99-0.02InSb composite at 300 K, resulting in an average power factor of 23.8 μW cm^-1 K^-2 from 300 K to 553 K. To address the efficiency degradation caused by the narrow operational temperature range of MgAgSb, a two-pair segmented thermoelectric module is developed. A high conversion efficiency of 12.4% is achieved under a cold-side temperature of ~293 K and a temperature difference of ~540 K, presenting an effective strategy for carrier mobility optimization and opening new avenues for medium-temperature waste heat harvesting using MgAgSb.