Core-Shell BaTiO3 Capacitor Composition for High-Temperature Capacitance
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Solution Overview
Problem
Conventional capacitors have a lower relative dielectric constant and capacitance due to the presence of different phases and grain boundary phases in the dielectric layers, which reduces their performance in terms of capacitance and insulation resistance, especially at high temperatures.
Innovation Solution
The capacitor design incorporates dielectric layers with crystal grains of barium titanate, rare earth elements, and silicon, featuring a core-shell structure where the first crystal grains have a higher rare earth element concentration in the shell than the core, and the second crystal grains have a lower silicon concentration ratio in the shell compared to the core, increasing the combined dielectric constant and insulation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dielectric layers with different phases and grain boundary phases are used, then the capacitor can be manufactured with standard materials, but the relative dielectric constant and capacitance are reduced
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the shell region contains a higher concentration of rare earth elements compared to the core. This localized compositional variation enhances the dielectric constant specifically at the grain boundaries and surfaces, directly addressing the problem of reduced capacitance caused by conventional uniform compositions with harmful phases.
Solution Approach 2:
The patent employs composite materials by combining barium titanate with rare earth elements and silicon in a specific core-shell configuration. This composite approach creates a material system where the shell region (with higher rare earth content) and core region (with lower rare earth content) work together to achieve both high dielectric constant and improved insulation resistance, overcoming the limitations of single-phase conventional materials.
2Reliability
If dielectric layers contain multiple phases and grain boundary phases, then the manufacturing process is simplified, but insulation resistance decreases especially at high temperatures
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the shell region contains a higher concentration of rare earth elements compared to the core. This localized compositional variation enhances the dielectric constant specifically at the grain boundaries and surfaces, directly addressing the problem of reduced capacitance caused by conventional uniform compositions with harmful phases.
Solution Approach 2:
The patent employs composite materials by combining barium titanate with rare earth elements and silicon in a specific core-shell configuration. This composite approach creates a material system where the shell region (with higher rare earth content) and core region (with lower rare earth content) work together to achieve both high dielectric constant and improved insulation resistance, overcoming the limitations of single-phase conventional materials.
Data Source
AI summary
A capacitor body includes a plurality of dielectric layers and a plurality of internal electrode layers stacked alternately. The plurality of dielectric layers include crystal grains of barium titanate, a rare earth element, and silicon. The crystal grains include a first crystal grain and a second crystal grain. The crystal grains each include a surface layer as a shell and an interior portion surrounded by the shell as a core. The first crystal grain has a higher concentration distribution of the rare earth element in the shell than in the core. The second crystal grain has distribution in which a ratio of a concentration of the silicon in the core and the shell is lower than a ratio of a concentration of the rare earth element in the core and the shell in the first crystal grain.