Solid Electrolytic Capacitor Viscosity Control via Polyanion Seed
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Solution Overview
Problem
The miniaturization and high-frequency performance requirements of electronic devices necessitate solid electrolytic capacitors with improved impedance characteristics, but conductive polymers tend to agglomerate, increasing viscosity in dispersion media, making their industrial handling inconvenient and requiring enhanced conductivity and impregnation properties.
Innovation Solution
A method involving a conjugated conductive polymer-containing dispersion liquid with a seed particle as a protective colloid formed from a polyanion is used, which is polymerized and attached to a porous anode body to form a solid electrolyte layer without increasing viscosity, achieving excellent conductivity and impregnation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive polymer is used as solid electrolyte, then capacitor characteristics are improved, but viscosity of dispersion liquid increases due to agglomeration
Solution Approach 1:
A surfactant is introduced as an intermediary substance between the conductive polymer and the dispersion medium. The surfactant adsorbs onto the polymer surface, preventing agglomeration and maintaining low viscosity while preserving the polymer's electrical conductivity and capacitor performance.
Solution Approach 2:
The chemical composition parameters of the dispersion liquid are modified by adding specific surfactants and adjusting concentrations. This changes the interfacial properties and steric stabilization, preventing polymer aggregation and maintaining workable viscosity levels.
2Reliability
If conductive polymer concentration is increased, then conductivity is improved, but viscosity increases making industrial handling difficult
Solution Approach 1:
Surfactants serve as mediators that enable higher polymer concentrations to be achieved without proportional increases in viscosity. The surfactant layer prevents polymer-polymer interactions that would otherwise cause aggregation and viscosity surge.
Solution Approach 2:
The dispersion liquid is formulated as a composite system containing conductive polymer, surfactant, and dispersion medium. This composite structure leverages the surfactant's steric and electrostatic stabilization to maintain fluidity at high polymer loadings.
3Manufacturing precision
If polymerization is performed, then solid electrolyte layer is formed, but viscosity increases during reaction
Solution Approach 1:
The surfactant is pre-added to the dispersion medium before polymerization begins. This preliminary action ensures that as polymer chains form and grow during polymerization, they are immediately stabilized by the surfactant, preventing aggregation and viscosity increase throughout the reaction process.
Solution Approach 2:
The surfactant acts as a mediator during polymerization, interfacing between the growing polymer chains and the dispersion medium. This continuous stabilization during the reaction maintains manageable viscosity while the solid electrolyte layer forms.
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
This method effectively synthesizes a solid electrolytic capacitor with superior capacitor characteristics, including high capacitance and low equivalent series resistance, while maintaining manageable viscosity during polymerization.
Implementation Method 1
polymerizing the monomer to obtain a conjugated conductive polymer-containing dispersion liquid
Implementation Method 2
attaching the conjugated conductive polymer-containing dispersion liquid to the surface of a porous anode body
Implementation Method 3
removing a part or all of the dispersion medium from the conjugated conductive polymer-containing dispersion liquid attached to the porous anode body
Implementation Method 4
forming a dielectric oxide film on a metal surface through anodic oxidation
Data Source
AI summary
A method for manufacturing a solid electrolytic capacitor, which includes the steps of: in a dispersion medium containing a monomer for obtaining a conjugated conductive polymer and a seed particle with protective colloid formed of a polyanion, polymerizing the monomer to obtain a conjugated conductive polymer-containing dispersion liquid; attaching the conjugated conductive polymer-containing dispersion liquid to the surface of a porous anode body at least having an anode body made of a valve metal and a dielectric film formed on the surface of the anode body; and removing a part or all of the dispersion medium from the conjugated conductive polymer-containing dispersion liquid attached to the porous anode body to form a solid electrolyte layer. Also disclosed is a solid electrolytic capacitor obtained by the method.