High aspect ratio Na–Co-oxide ceramic filler composites with novel electrical and dielectric properties

• Published in: Composites communications Vol. 48; p. 101904
• Main Authors: Ghosh, Dipankar, Jin, Geng Bang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2024
• Subjects: Dielectric composites; Electrical stress control; Nonlinear ceramics; Sodium cobalt oxide; Varistor; Varistor; Nonlinear ceramics; Dielectric composites; Sodium cobalt oxide; Electrical stress control
• ISSN: 2452-2139; 2452-2139
• DOI: 10.1016/j.coco.2024.101904

Polymer composites with high aspect ratio Na–Co oxide ceramic filler – polymer matrix was investigated in this study. They demonstrate high dielectric permittivity, low dielectric loss tangent values which is useful for capacitive field grading and reversible voltage dependent electrical conductivity properties under an applied electric field which can be utilized for resistive field grading. These unique properties are useful for electrical stress control applications in power components. This study employs novel ceramic platelets as the varistor filler component in a polymer composite form, introducing a new class of materials to the world of electrical stress control technology. By minimizing the amount of varistor filler material required to very low levels (15 wt%), it is possible to develop lightweight non-linear dielectric composites that not only exhibit improved electrical characteristics but also make processing easier and open up new design space for making various components for electrical power applications. By utilizing novel NaxCoO2 (x < 1) ceramic fillers in composite form, we aim to contribute to the development of innovative nonlinear dielectric composites that can enhance the performance and processibility of various power system components under various working environments. [Display omitted] •This study introduces novel composite materials with excellent electric stress control properties suitable for electrical power components.•These composites contain novel NaxCoO2 ceramic platelets, which have not been previously studied for electrical stress control applications.•They possess a unique combination of high dielectric permittivity values for efficient electric field distribution and low dielectric loss.•The composites also exhibit a voltage-dependent nonlinearity, like a ceramic varistor, providing efficient resistive grading performance.•This nonlinearity can be further tuned by using NaxCoO2 ceramics with different aspect ratios.•The record low amount (< 15 wt.%) of ceramic fillers required to achieve these properties makes them appealing for practical applications.•Such multifunctional composites would alleviate several issues such as size, functionality, and performance for many power applications.