Cold sintered BaTiO₃–poly(ether imide) nanocomposites with superior comprehensive performances

With the rapid development of electronic industry, the demands for dielectric materials with high permittivities, low losses, and excellent electrical breakdown strengths prepared via low temperature fabrication techniques are increasing. Herein, we propose one-step cold sintering process route to improve the comprehensive performances of BaTiO₃ based ceramics by integrating PEI. Dense BaTiO₃-PEI nanocomposites can be prepared via cold sintering process at 250 °C using Ba(OH)₂∙8H₂O and H₂TiO₃ as the transient liquid phase. The grain growth of BaTiO₃ is inhibited and thin PEI layers with less than 10 nm are located at the grain boundaries. The dissolution-precipitation process triggered by transient liquid phase and viscos flow assisted by PEI dominate the cold sintering mechanism of (1-x)BaTiO₃-xPEI nanocomposites. The dielectric properties are stable over a broad temperature range up to 200 °C. Superior performances with a relative permittivity of 163 and a low dielectric loss of 0.014 are obtained in 80BaTiO₃-20PEI nanocomposites, and the electrical breakdown strength is increased by 80.65% compared with BaTiO₃. Overall, cold sintering process provides a potential way to develop dielectric nanocomposites with excellent comprehensive performances.