PEDOT Dispersion Filtration for Higher-Capacitance Capacitor Layers

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Solution Overview

Problem

Conventional PEDOT/PSS dispersions used in solid electrolyte capacitors often result in capacitance that is not high enough for certain applications, limiting their performance.

Innovation Solution

A dispersion comprising a polythiophene, preferably in the form of a PEDOT/PSS complex, with specific particle size and conductivity characteristics is developed, allowing for the preparation of solid electrolyte layers with enhanced capacitance. The dispersion is formulated to have a controlled number of particles per ml and conductivity, optimized through processes like high-pressure homogenization and filtration, to achieve improved electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional PEDOT/PSS dispersions are used to prepare solid electrolyte layers, then the processing is simple, but the capacitance is not high enough for certain applications

Engineering Contradiction:
Improveprocessing simplicityVSAvoidcapacitance performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the particle size distribution parameters of the PEDOT/PSS dispersion by applying high-pressure homogenization (reducing particles to sub-micron size) and controlled filtration. This parameter modification enables the dispersion to form solid electrolyte layers with sufficient capacitance while maintaining a relatively simple two-step processing procedure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the particle size distribution into specific ranges: particles larger than 10 μm are removed by filtration, while particles in the 0.1-10 μm range (particularly 1-5 μm) are retained to provide adequate capacitance. This segmentation approach optimizes the balance between processing simplicity and performance.

Inventive Principle:
Principle #1Segmentation

2Reliability

If high-pressure homogenization and filtration are applied to control particle size, then the conductivity and capacitance are improved, but the process complexity increases

Engineering Contradiction:
Improveelectrical conductivity and capacitanceVSAvoidprocess steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the particle treatment into two distinct operations: high-pressure homogenization to reduce particle size to sub-micron dimensions, followed by filtration to remove particles larger than 10 μm. This segmentation achieves optimal conductivity and capacitance through controlled particle size distribution while keeping the process relatively simple.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements continuous high-pressure homogenization (applying multiple passes at 100-1000 bar) followed by continuous filtration, creating a streamlined process that maintains particle size control without requiring intermediate storage or handling steps, thereby reducing overall process complexity.

Inventive Principle:
Principle #20Continuity of useful 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 resulting solid electrolyte layers exhibit increased capacitance and conductivity, addressing the limitations of conventional PEDOT/PSS dispersions and enabling higher performance in capacitors.

Implementation Method 1

The dispersion is formulated to have a controlled number of particles per ml and conductivity, optimized through processes like high-pressure homogenization

Methodology Applied
Scientific EffectHomogenization:

Implementation Method 2

optimized through processes like high-pressure homogenization and filtration, to achieve improved electrical conductivity

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 3

A dispersion comprising a dispersant and at least one polythiophene dispersed in the dispersant

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentEP4465317A1Pedot-dispersion with low number of particles
Publication Date: 2024.11.20 HERAEUS EPURIO GMBH
  • EP4465317A1 patent drawingFigure 1
  • EP4465317A1 patent drawingFigure 2
  • EP4465317A1 patent drawing

AI summary

The present invention relates to a dispersion comprising i) a dispersant; ii) at least one polythiophene dispersed in the dispersant i); wherein the dispersion comprises less than 10,000 particles per ml that have a particle size of 1.5 µm or more; and wherein a conductive layer prepared from the dispersion has a conductivity of more than 10 S/cm as determined by the test method disclosed herein. The invention also relates to a process for the preparation of a dispersion, to a dispersion obtainable by that process, to a process for the preparation of a layered body, to a layered body obtainable by that process and to the use of a dispersion for the formation of a solid electrolyte layer in a capacitor.