Colossal Permittivity Ceramics: Fundamental Mechanisms, Structure-Property Coupling, and Design Perspectives

Colossal permittivity (CP) ceramics have garnered significant attention for their potential in high-energy-density capacitors and advanced electronic devices. Recent progress has been made across representative systems, including CaCu 3 Ti 4 O 12 , BaTiO 3 -based, TiO 2 -based, high-entropy, and composite or core-shell ceramics, each exhibiting distinct structural and polarization characteristics. The dielectric enhancement in these materials arises from the interplay of intrinsic and extrinsic mechanisms, primarily involving defect dipole polarization, internal and surface barrier layer capacitance, and space charge driven interfacial polarization. These mechanisms collectively govern dielectric behavior by balancing charge localization and interfacial polarization. Despite considerable advances, achieving high permittivity together with low dielectric loss and reliable stability remains a challenge. Continued efforts in defect engineering, interface modulation, and structural design are expected to enable the development of next-generation CP ceramics with superior dielectric performance and long-term reliability.