Colossal Permittivity Materials as Superior Dielectrics for Diverse Applications

Ever since the beginning of this century, many kinds of materials have been reported to demonstrate colossal permittivity (CP) or a colossal dielectric constant exceeding 10(3). Accordingly, such CP materials and their further modification and improvement to achieve enhanced CP performance for promising applications in modern electronics, sensors, energy storage, and multifunctional devices have attracted extensive attention. In this Review, a general overview of the recent advances in CP materials is provided, ranging from their various categories, physical mechanisms, and modulation methods to promising applications. First, various classes of CP materials are categorized in terms of their structures and dielectric properties. Subsequently, this Review provides an insight into the CP mechanisms in views of barrier layer capacitance, defect-dipole cluster, and polaronic effect. Moreover, the strategies and prototypical works are introduced in some aspects, including the manipulation of CP properties by doping, percolative capacitors, and the methods employed to enhance the dielectric behaviors in CP materials with different forms. The authors then discuss a wide range of applications based on CP materials, such as modern electronics and energy storage. Finally, the challenges and opportunities for further investigation of CP materials are highlighted in the summary and future perspectives.