Solid Electrolytic Capacitor Mordant Layer for ACC Reduction
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Solution Overview
Problem
Solid electrolytic capacitors with polythiophene-based conductive polymers exhibit anomalous charging current (ACC) exceeding theoretical limits, which can disrupt circuit functions during thorough drying, posing reliability issues.
Innovation Solution
Incorporating a mordant layer between the dielectric and conductive polymer layers, composed of a specific mordant compound and crosslinker, to reduce anomalous charging current (ACC) and enhance capacitor reliability in high temperature and humidity conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thorough drying is performed on solid electrolytic capacitors with polythiophene-based conductive polymers, then moisture is removed from the capacitor, but anomalous charging current (ACC) increases beyond theoretical limits
Solution Approach 1:
A mordant layer is introduced as an intermediary between the dielectric layer and the conductive polymer layer. This mordant layer, comprising chromium(III) oxide and chromium(III) hydroxide, acts as a mediator that prevents direct harmful interactions during drying, thereby reducing anomalous charging current while maintaining capacitor reliability.
Solution Approach 2:
The capacitor structure employs composite materials by combining the dielectric layer, mordant layer (chromium(III) oxide and chromium(III) hydroxide), and conductive polymer layer. This composite structure leverages the beneficial properties of each material while mitigating their individual drawbacks, particularly the ACC issue during drying.
2Reliability
If a mordant layer is incorporated between the dielectric and conductive polymer layers, then anomalous charging current is reduced and reliability is improved, but device complexity increases
Solution Approach 1:
The capacitor is segmented into distinct functional layers: a dielectric layer, a mordant layer (comprising chromium(III) oxide and chromium(III) hydroxide), and a conductive polymer layer. This segmentation allows each layer to perform its specific function optimally while managing overall complexity through modular design.
Solution Approach 2:
The mordant layer serves multiple functions simultaneously: it acts as an adhesion promoter between layers, a barrier to moisture and oxygen, and a stabilizer that reduces anomalous charging current. This multi-functionality justifies the added structural complexity by delivering multiple benefits from a single layer.
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 mordant layer significantly reduces ACC, improving capacitor reliability and performance under high temperature and humidity conditions, as demonstrated by reduced ESR and leakage current shifts.
Implementation Method 1
a mordant layer between the dielectric and conductive polymer layer and between adjacent conductive polymer layers wherein the mordant layer comprises a mixture or reactive product of represented by the mordant compound of Formula A and crosslinker
Data Source
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AI summary
The present invention if related to an improved electrolytic capacitor and a method of making the improved electrolytic capacitor. The electrolytic capacitor comprises an anode comprising a dielectric layer on the anode. A first mordant layer is on the dielectric wherein the first mordant layer comprises a mordant compound of Formula A: wherein: R1 and R2 is independently selected from H; cation, linear alkyl, cyclic alkyl or substituted alkyl of 1 to 10 carbons; R3 is selected from -CR4R5R6 wherein R4 represents a hydrogen, an alkyl of 1-20 carbons or an aryl of 6-20 carbons; R4 and R5 can be taken together to represent a cyclic alkyl or substituted cyclic alkyl or (-CR6OP(O)OR1OR2)n; R5 represents an alkyl of 1-20 carbons or an aryl of 6-20 carbons; R4 and R5 can be taken together to represent a cyclic alkyl or substituted cyclic alkyl or (-CR6OP(O)OR1OR2)n; R6 represents a hydrogen, an alkyl of 1-20 carbons or an aryl of 6-20 carbons; and n is an integer from 1 to 20; and a crosslinker. A primary conductive polymer layer is on the first mordant layer.