Capacitor Solid Electrolyte Using Mixed Conductive Polymers
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Solution Overview
Problem
Existing capacitor production methods, particularly for solid electrolytic capacitors, face challenges such as complex processes, use of flammable or toxic solvents, and unsatisfactory low-temperature performance due to unstable counter-ions and high equivalent series resistance (ESR).
Innovation Solution
A process involving the introduction of a dispersion containing a foreign-doped conductive polymer and self-doped conductive polymer into an electrode body, where the dispersing agent is removed to form a solid electrolyte, allowing for improved capacitance and low-temperature properties with reduced technical complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If in situ polymerization is used to produce solid electrolyte, then the electrolyte can be formed directly on the oxide layer, but the process becomes complex and requires multiple steps including impregnation, polymerization and washing lasting several hours
Solution Approach 1:
The conductive polymer is pre-synthesized and prepared as a dispersion before being applied to the oxide layer. This preliminary preparation eliminates the need for in-situ polymerization steps, reducing process complexity while maintaining electrolyte formation quality
Solution Approach 2:
The polymerization step is extracted from the capacitor manufacturing process. Instead of polymerizing monomers within the capacitor structure, the conductive polymer is synthesized separately and applied as a ready-made dispersion, removing the complex polymerization chemistry from the production line
2Ease of manufacture
If small anions of oxidizing agent are used as counter-ions, then the polymerization can proceed, but the counter-ions are not bonded stably and diffuse at elevated temperatures increasing ESR
Solution Approach 1:
The counter-ion is changed from small monomeric anions to large polymeric anions (polysulfonates, polyacrylates, polyalkylacrylates). This parameter change in ion size and structure provides stable bonding to the conductive polymer while maintaining electrical conductivity, preventing diffusion at elevated temperatures
Solution Approach 2:
The invention creates a composite structure where the conductive polymer is combined with polymeric counter-ions to form a stable solid electrolyte composite. This composite material integrates the conductivity of the polymer with the stability of the polymeric counter-ion, achieving both electrical performance and thermal stability
3Device complexity
If dispersions of already polymerized thiophene with polyanion counter-ions are used, then the process is simpler, but the capacitors show low capacitance and unsatisfactory low temperature properties
Solution Approach 1:
The dispersion composition is optimized by adjusting the ratio of conductive polymer to polymeric counter-ion, the molecular weight and structure of the counter-ion, and the dispersing agent. These parameter changes improve low-temperature performance while maintaining process simplicity
Solution Approach 2:
The invention creates an optimized composite material using specifically selected conductive polymers (such as polythiophenes, polypyrroles, polyanilines) combined with polymeric counter-ions in a controlled dispersion. This composite structure maintains simplicity while improving low-temperature capacitance and electrical characteristics
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 process results in capacitors with low ESR and adequate capacitance, maintaining performance even at low temperatures, thus overcoming the limitations of previous methods.
Implementation Method 1
PEDOT), since it has a very high conductivity in its oxidized form
Implementation Method 2
a dispersion comprising the already polymerized thiophene and a polyanion as a counter-ion... is applied to the oxide layer and the dispersing agent is then removed by evaporation
Data Source
Figure 1
AI summary
The present invention relates to a process for the production of a capacitor, comprising the process steps: a) the provision of an electrode body (1) of an electrode material (2), wherein a dielectric (3) covers one surface (4) of this electrode material (2) at least partly under formation of an anode body (5); b) the introduction of a dispersion comprising a dispersing agent, a foreign- doped conductive polymer and counter-ions which are not covalently bonded to the foreign-doped conductive polymer into at least a part of the anode body (5); c) the at least partial removal of the dispersing agent under obtaining a solid electrolyte (6) in a capacitor body; wherein a self-doped conductive polymer is additionally introduced into at least a part of the anode body (5). The present invention also relates to the capacitor obtainable by this process, a capacitor, electronic circuits, the use of a capacitor and a dispersion.