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

With the rapid development of the electronics industry, the demand for dielectric materials with high permittivities, low losses, and excellent electrical breakdown strengths prepared via low-temperature fabrication techniques is increasing. Herein, we propose a one-step cold sintering process route to improve the comprehensive performance of BaTiO₃−based ceramics by integrating polyetherimide (PEI). Dense BaTiO₃–PEI nanocomposites can be prepared via a 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 less than 10 nm in size are located at the grain boundaries. The dissolution‒precipitation process triggered by the transient liquid phase and viscous flow assisted by PEI dominates the cold sintering mechanism of the (1−x)BaTiO₃–xPEI nanocomposites. The dielectric properties are stable over a broad temperature range up to 200 °C. Compared with BaTiO₃, 80% BaTiO₃–20% PEI has superior performance, with a relative permittivity of 163 and a low dielectric loss of 0.014, and the electrical breakdown strength is increased by 80.65% compared with BaTiO₃. Overall, the cold sintering process provides a potential way to develop dielectric nanocomposites with excellent comprehensive performance.