Core-shell nanoparticles toughen cathode binder
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Solution Overview
Problem
Solid electrolytic capacitors face challenges with thermoset resin binders being brittle and prone to cracking under thermo-mechanical stress, while thermoplastic polymers improve toughness but compromise moisture barrier and humidity resistance.
Innovation Solution
Incorporating core-shell particles with a flexible core and a reactive resin shell that cross-links with the binder to create a toughened thermoset matrix, enhancing flexibility and thermal stability without compromising moisture barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermoset resin binders are used in cathode layers, then thermal stability and chemical resistance are improved, but brittleness increases and crack formation occurs under thermo-mechanical stress
Solution Approach 1:
The patent uses a composite binder system combining thermoset resin (for thermal stability) with elastomeric polymer particles (for flexibility and crack resistance). This composite approach allows the cathode layer to simultaneously achieve high temperature resistance and mechanical toughness, resolving the contradiction between thermal stability and brittleness.
2Strength
If thermoplastic polymers are added to toughen thermoset resins, then flexibility and crack resistance are improved, but moisture barrier properties and humidity resistance deteriorate
Solution Approach 1:
The patent incorporates elastomeric polymer particles with flexible shells that can deform to absorb thermal stress and prevent crack formation. These flexible shells provide the necessary toughness while the controlled particle size and distribution ensure that moisture barrier properties are maintained, resolving the contradiction between toughness and moisture resistance.
3Strength
If core shell particles with flexible core and reactive resin shell are used, then flexibility and thermal stability are improved, but manufacturing complexity increases
Solution Approach 1:
The core-shell particles are pre-synthesized with the flexible core and reactive resin shell structure before being incorporated into the cathode layer. This preliminary preparation of the composite particles simplifies the manufacturing process by eliminating the need for complex in-situ crosslinking or multi-step processing, making the production more straightforward while maintaining the desired flexibility and thermal stability properties.
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 use of core-shell rubber particles significantly improves the humidity performance and thermal stability of cathode layers, reducing ESR shifts and crack formation under stress conditions.
Implementation Method 1
a reactive resin shell that cross-links with the binder to create a toughened thermoset matrix
Implementation Method 2
core shell particles with a flexible core and a reactive resin shell
Data Source
AI summary
Provided herein is a capacitor, and method for forming a capacitor, comprising an anode, a dielectric over the anode; a cathode over the dielectric; and the cathode comprises core shell particles.