Polymer Electrolyte Films for Transparent, Fast-Switching Smart Windows
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Solution Overview
Problem
Existing electrolyte films for electrochromic windows suffer from poor optical clarity due to incompatibility between polymers and plasticizers, which compromises their suitability for smart window applications.
Innovation Solution
Formulations are developed with specific organic carbonates and second plasticizer materials that maintain ionic conductivity while ensuring optical transparency by keeping the Hansen Solubility Parameter (Ra) between the plasticizer and polymer below 5.0, preferably 3.79, using a combination of diethyl carbonate, propylene carbonate, and other additives like dibenzoate or acrylic monomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid polymeric interlayer electrolyte is used to eliminate electrolyte leakage, then safety and reliability are improved, but ionic conductivity deteriorates
Solution Approach 1:
The patent uses a composite electrolyte system combining a solid polymeric interlayer (providing structural integrity and leakage prevention) with a liquid electrolyte impregnated within the polymer matrix (providing high ionic conductivity). This composite structure allows the electrolyte to maintain both safety characteristics of solid-state and high conductivity characteristics of liquid-state electrolytes.
2Power
If a polymer is plasticized with a liquid electrolyte to improve ionic conductivity, then ionic conductivity is improved, but optical clarity deteriorates due to incompatibility between polymer and plasticizer
Solution Approach 1:
The patent modifies the chemical parameters of the polymer electrolyte system by selecting specific polymer materials and plasticizer combinations with compatible chemical structures and physical properties. This parameter optimization ensures that the plasticized polymer maintains optical clarity while achieving the desired ionic conductivity enhancement.
Solution Approach 2:
The patent develops a composite electrolyte formulation where the polymer and liquid electrolyte are carefully selected to be mutually compatible, creating a homogeneous composite material that maintains optical transparency while providing high ionic conductivity through the liquid electrolyte phase dispersed within the polymer matrix.
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 provides electrochromic cells with high optical clarity, ionic conductivity, and rapid switching speeds, suitable for smart windows with transmittance greater than 80% and switching times under 1 minute.
Implementation Method 1
the plasticizer and the polymer layer are completely dissolve into each other in solution
Implementation Method 2
The electrolyte layer is a pure ion conductor and separates the two EC layers
Implementation Method 3
Optical absorption occurs when electrons move into the EC layers from the transparent conductors
Implementation Method 4
Electrochromism is a phenomenon where the color or opacity of a material changes depending on the application of voltage
Data Source
AI summary
Provided are electrolyte films or cells for use in variety of applications, such as electrochromic windows. An electrolytic film comprises a polymer layer, such as thermoplastic polyurethane or polymethyl methacrylate, and an electrolyte within the polymer layer. The electrolyte comprises a salt and a plasticizer. The plasticizer comprises one or more materials that are selected to provide sufficient conductivity and optical transparency for operation of the electrolyte film in an application requiring substantial optical clarity and switching speed, such as a smart window.