Enhanced Absolute Recovered Energy under Low Electric Field in All‐Inorganic 0–3 Nanocomposition Thick Films

Abstract Inorganic thick‐film dielectric capacitors with ultrahigh absolute recovered energy at low electric fields are extremely desired for their wide application in pulsed power systems. However, a long‐standing technological bottleneck exists between high absolute energy and large recovered energy density. A new strategy is offered to fabricate selected all‐inorganic 0–3 composite thick films up to 10 µm by a modified sol‐slurry method. Here, the ceramic powder is dispersed into the sol‐gel matrix to form a uniform suspension, assisted by powder, therefore, the 2 µm‐thickness after single layer spin coating. To enhance the energy‐storage performances, the composites process is thoroughly optimized by ultrafine powder (<50 nm) technique based on a low‐cost coprecipitation method instead of the solid‐state and sol‐gel methods. 0D coprecipitation powder has a similar dielectric constant to the corresponding 3D films, thus uneven electrical field distributions is overcome. Moreover, the increase of interfacial polarization is realized due to the larger specific surface area. A maximum recoverable energy density of 14.62 J cm ⁻³ is obtained in coprecipitation thick films ≈2.2 times that of the solid‐state powder and ≈1.3 times for sol‐gel powder. This study provides a new paradigm for further guiding the design of composite materials.