Conductive Polymer Electrolyte Layer for Stable High-Temperature Capacitors

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Solution Overview

Problem

The life-time of electrolytic capacitors, particularly those with solid electrolyte layers based on π-conjugated polymers like PEDOT/PSS, is limited by the degradation of electrical parameters such as equivalent series resistance (ESR) and dissipation factor, especially when operated at elevated temperatures.

Innovation Solution

A process for preparing a layered body involving the application of a liquid composition containing a conductive polymer, dispersant, and aromatic nitro compound, followed by partial removal of the dispersant, to form a stable solid electrolyte layer in capacitors, which includes specific weight percentages and particle sizes of the components to maintain stability at high temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a solid electrolyte layer based on π-conjugated polymers (e.g., PEDOT/PSS) is used in electrolytic capacitors, then the electrical conductivity is improved, but the stability of electrical parameters (ESR and dissipation factor) deteriorates at elevated temperatures

Engineering Contradiction:
Improveelectrical conductivityVSAvoidstability of electrical parameters
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition of the liquid composition used to form the solid electrolyte layer. Specifically, it introduces aromatic nitro compounds (iii) in controlled amounts (0.025-0.9 wt.-%) into the liquid composition containing conductive polymers (i) and dispersants (ii). This chemical parameter modification enables the resulting solid electrolyte layer to maintain both high electrical conductivity and improved stability of electrical parameters at elevated temperatures, thus resolving the contradiction between conductivity and reliability.

Inventive Principle:
Principle #35Parameter changes

2Power

If the capacitor is operated at elevated temperatures to improve performance, then the power output is improved, but the degradation of electrical parameters (ESR and dissipation factor) accelerates

Engineering Contradiction:
Improvepower outputVSAvoidlife-time
Core Design Contradiction:
PowerVSDuration of action of stationary object

Solution Approach 1:

The patent applies preliminary anti-action by incorporating aromatic nitro compounds (iii) into the liquid composition before the capacitor is assembled and put into operation. These compounds pre-establish protective effects that counteract the degradation processes that would normally accelerate at elevated temperatures. By having this protective mechanism in place beforehand, the capacitor can operate at higher temperatures for extended periods without experiencing accelerated degradation of electrical parameters, thus extending its operational life-time while maintaining power output.

Inventive Principle:
Principle #9Preliminary anti-action

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 solution significantly reduces changes in dissipation factor and ESR, ensuring capacitor stability even at elevated temperatures, thereby extending the life-time and performance of electrolytic capacitors.

Implementation Method 1

a liquid composition comprising i) a conductive polymer; ii) a dispersant in which the conductive polymer is dispersed

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

The solution significantly reduces changes in dissipation factor and ESR, ensuring capacitor stability even at elevated temperatures

Methodology Applied
Scientific EffectThermal stabilization:

Data Source

PatentEP4668303A1Conductive polymer dispersions for improved stability performance of capacitors
Publication Date: 2025.12.24 HERAEUS EPURIO GMBH
  • EP4668303A1 patent drawingFigure 1
  • EP4668303A1 patent drawingFigure 2
  • EP4668303A1 patent drawing

AI summary

The present invention relates to a process for the preparation of a layered body (100), comprising the process steps: A) provision of a substrate (101); B) application of a liquid composition onto at least a part of a surface of this substrate (101), wherein the liquid composition comprises i) a conductive polymer; ii) a dispersant in which the conductive polymer is dispersed; iii) an aromatic nitro compound; wherein the liquid composition comprises the aromatic nitro compound iii) in an amount in the range from 0.025 to 0.9 wt.-%, based on the weight of the liquid composition. C) at least partial removal of the dispersant ii) to obtain a layered body (100) comprising an electrically conductive layer (102) coated onto at least a part of the surface of the substrate (101). The invention also relates to a layered body, to an electronic device comprising a layered body, to a liquid composition and to the use of a liquid composition for the preparation of a layered body in an electronic device.