Electrodeposited Dielectric Oxide for High-Capacitance Solid Capacitors
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Solution Overview
Problem
Conventional solid electrolytic capacitors face limitations in achieving high surface area and thus low capacitance and energy density due to the quality of their dielectric materials.
Innovation Solution
A method for forming a solid electrolytic capacitor using an anode with a valve metal composition, where a dielectric oxide layer is electrodeposited using an electrolyte containing an ionic liquid and a valve metal salt, with a hydrophobic cationic species and counterion to minimize moisture and enhance dielectric formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional anodic oxidation is used to form a dielectric, then the process is simple and well-established, but the dielectric lacks sufficient quality to achieve high surface area, limiting capacitance and energy density
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by replacing conventional aqueous electrolytes with ionic liquids containing specific cations (e.g., imidazolium, pyridinium) and anions (e.g., BF4-, PF6-). This parameter change transforms the dielectric formation process, enabling higher surface area and improved dielectric quality while maintaining a straightforward electrodeposition procedure
Solution Approach 2:
The patent employs composite ionic liquid electrolytes combining specific cationic species with anionic species to create a synergistic effect. This composite approach allows the dielectric to achieve superior surface area and capacitance properties that cannot be obtained with conventional single-component electrolytes
2Quantity of substance
If the dielectric surface area is increased to improve capacitance, then energy density improves, but the dielectric quality must be maintained to prevent breakdown
Solution Approach 1:
By changing the electrolyte composition to ionic liquids with specific cation-anion combinations, the patent achieves simultaneous improvement in dielectric surface area and breakdown resistance. The ionic liquid parameters enable formation of a dielectric with both high surface area and high quality, resolving the trade-off between quantity and reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The approach results in capacitors with improved capacitance, energy density, and breakdown voltage, maintaining low equivalent series resistance and leakage current even under extreme conditions.
Implementation Method 1
forming the dielectric by a process that includes placing the anode into contact with an electrolyte containing an ionic liquid and a valve metal salt and applying a potential difference between the anode and a counter electrode to form a dielectric oxide layer
Implementation Method 2
an electrolyte containing an ionic liquid and a valve metal salt, with the cationic species and counterion selected so as to minimize the presence of moisture
Data Source
AI summary
A method for forming a solid electrolytic capacitor that includes an anode containing a valve metal composition, a dielectric overlying the anode, and a solid electrolyte overlying the dielectric is provided. The method comprises forming the dielectric by a process that includes placing the anode into contact with an electrolyte containing an ionic liquid and a valve metal salt and applying a potential difference between the anode and a counter electrode to form a dielectric oxide layer.