High Energy Density, High Temperature Capacitors Utilizing Mn‐Doped 0.8CaTiO₃–0.2CaHfO₃ Ceramics

Abstract

Single layer air co-fired capacitors with Pt internal electrodes were prototyped for the compositions 0.8CaTiO 3 -0.2CaHfO 3 (CHT) and 0.5 mol% Mn-doped 0.8CaTiO 3 -0.2CaHfO 3 (CHT + Mn) to yield a material with a room-temperature relative permittivity of e r~1 70, thermal coefficient of capacitance (TCC) of ±15.8% to ±16.4% from À50°C to 150°C, and a band gap of~4.0 eV. Impedance spectroscopy revealed that doping with Mn reduces both the ionic and electronic conductivity. Undoped CHT single layer capacitors exhibited ambient energy densities as large as 9.0 J/cm 3 , but showed a drastic decrease in energy density above 100°C. When doped with 0.5 mol% Mn, the temperature dependence of the breakdown strength was minimized, and energy densities similar to ambient values (9.5 J/cm 3 ) were observed up to 200°C. At 300°C, energy densities as large as 6.5 J/cm 3 were measured. The design rationale for these dielectrics centered on materials with large band gaps, linear or weakly nonlinear permittivities, and high breakdown strengths. These observations suggest that with further reductions in grain size and dielectric layer thickness, the CaTiO 3 -CaHfO 3 system is a strong candidate for integration into future power electronics applications.

Relaxor Ferroelectric BaTiO3–Bi(Mg2/3Nb1/3)O3 Ceramics for Energy Storage Application

“…There are four typical kinds of dielectrics for energy storage application: linear dielectric, ferroelectric, relaxor ferroelectric, and antiferroelectric . Although, linear dielectrics usually possess higher BDS and lower energy loss, their smaller polarization value (permittivity) makes them not suitable for high‐energy storage application, unless the multilayer ceramic capacitors (MLCC) technology is adopt [e.g., Ca(Zr,Ti)O 3 and 0.8CaTiO 3 –0.2CaHfO 3 ] . Ferroelectrics often have larger P s and moderate BDS, but their larger P r leads to a smaller energy storage density and lower efficiency .…”

Enhanced energy storage density by inducing defect dipoles in lead free relaxor ferroelectric BaTiO3-based ceramics

“…The low BDS and W rec of AFE and FE ceramics limit their application for high-voltage equipment and compact electronic devices. [7][8][9][10] So, it is important to search for the materials with a high BDS and W rec to enable the increasing demands for more compact electronic and energy storage devices.…”

MnO2 Thin Film Electrodes for Enhanced Reliability of Thin Glass Capacitors

“…High energy density dielectrics are utilized in power electronics and pulsed power applications to mitigate the problems associated with the size, temperature stability, and reliability of the energy storage devices. One approach to achieve the desired properties in energy storage devices is to enhance the energy density and power density of the dielectric materials . The amount of electrostatic energy that can be stored in a dielectric is strongly dependent on the dielectric constant and breakdown strength of the material.…”