Fast ion transport for synthesis and stabilization of β-Zn4Sb3

beta-Zn4Sb3 has promising thermoelectric performance, but its ionic migration properties make it prone to degradation. Here the authors exploit the ion migration in an electric field-assisted synthesis method, fast producing beta-Zn4Sb3 with improved phase stability and extended temperature range for the thermoelectric operation. Mobile ion-enabled phenomena make beta-Zn4Sb3 a promising material in terms of the re-entry phase instability behavior, mixed electronic ionic conduction, and thermoelectric performance. Here, we utilize the fast Zn2+ migration under a sawtooth waveform electric field and a dynamical growth of 3-dimensional ionic conduction network to achieve ultra-fast synthesis of beta-Zn4Sb3. Moreover, the interplay between the mobile ions, electric field, and temperature field gives rise to exquisite core-shell crystalline-amorphous microstructures that self-adaptively stabilize beta-Zn4Sb3. Doping Cd or Ge on the Zn site as steric hindrance further stabilizes beta-Zn4Sb3 by restricting long-range Zn2+ migration and extends the operation temperature range of high thermoelectric performance. These results provide insight into the development of mixed-conduction thermoelectric materials, batteries, and other functional materials.

Automated summary

Researchers have successfully synthesized beta-Zn4Sb3 with improved stability and extended temperature range using an electric field-assisted method, and found that the mobile ions play a crucial role in enhancing the thermoelectric performance of the material.