Direct Joule-Heated Non-Equilibrium Synthesis Enables High Performing Thermoelectrics

High-throughput synthesis of bulk inorganic materials is crucial for accelerating functional materials discovery but is hindered by slow, energy-intensive solid-state methods. We introduce Direct Joule-Heated Synthesis (DJS), a rapid, single-step and scalable solid-state synthesis technique achieving a 10⁵-fold speedup and 20,000× energy efficiency improvement over conventional synthesis. DJS enables the synthesis of dense, bulk chalcogenides (Bi _0.5 Sb _1.5 Te ₃ , AgSbTe₂), achieving a zT of 2.3 at 573 K in optimally Cd/Se co-doped AgSbTe₂, one of the highest for polycrystalline materials at this temperature. DJS enables optimal co-doping and rapid, non-equilibrium solidification, producing lamellar microstructures, interfacial regions, and cation-ordered nanodomains that scatter all-scale phonons, achieving ultralow lattice thermal conductivity (~ 0.2 W m⁻¹K⁻¹ at 573 K). DJS establishes a new benchmark for scalable and fast synthesis, accelerating functional material discovery.