Manipulating Atomic Disorder and Mesoscale Architectures for High‐Efficiency Thermoelectric Modules

core-shell precipitates. This hierarchical structural engineering acts as a frequency-selective barrier, drastically reducing lattice thermal conductivity without compromising carrier mobility. Consequently, the 0.5 mol% composite achieves a peak figure of merit of 1.47 at 333 K. Translating this material-level breakthrough into a device, we fabricated a thermoelectric module that delivers a conversion efficiency of ∼7% and an output power of 13.1 mW under a temperature difference of 180 K. This work establishes a generalizable protocol for functionalizing thermoelectric systems via coupled defect chemistry and interface engineering, bridging the gap between fundamental transport physics and practical energy harvesting.