Polymer Electrolyte Film Plasticizer Infusion for Ionic Conductivity
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Solution Overview
Problem
Existing methods struggle to produce free-standing polymer electrolyte films with high ionic conductivity and mechanical stability, particularly due to challenges with plasticizer content, handling, and incorporation of reactive species, which are sensitive to air and result in non-uniform films and loss of plasticizers during storage.
Innovation Solution
A method involving exposure of prefabricated polymer films to a solvent solution containing plasticizers and reactive compounds under controlled conditions to enhance ionic conductivity, followed by removal of excess solvent, resulting in a modified film with improved conductivity and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer films are extruded with high liquid plasticizer fractions to achieve high ionic conductivity, then ionic conductivity is improved, but the material becomes difficult to handle, stick to machine parts, and form non-uniform films
Solution Approach 1:
The patent divides the manufacturing process into two distinct stages: (1) extrusion of the polymer film with a lower plasticizer fraction (20-30 wt%) to ensure proper handling and uniform film formation, and (2) a subsequent soaking step where the extruded film is exposed to additional plasticizer to achieve the target high plasticizer fraction (40-60 wt%) for optimal ionic conductivity. This segmentation allows each stage to be optimized independently.
Solution Approach 2:
The patent performs the extrusion process first with controlled plasticizer content to establish a stable, handleable film structure. This preliminary action creates a robust base film that can be stored and transported before the final plasticizer infusion step, which preliminarily prepares the film for high conductivity applications.
2Reliability
If reactive species are incorporated during film fabrication to provide ionic conductivity, then electrochemical functionality is improved, but the reactive species react with air (H2O, O2, CO2) causing degradation and difficulty in production
Solution Approach 1:
The patent extracts the reactive species (lithium salts) from the extrusion process entirely. Instead of incorporating them during film fabrication, the film is extruded without reactive species, then subsequently soaked in solutions containing the reactive species. This extraction eliminates the air-sensitivity problem during the complex extrusion process while still achieving the desired electrochemical functionality in the final product.
Solution Approach 2:
The patent uses plasticizer solutions as intermediaries to transfer reactive species into the film. The plasticizer acts as a carrier medium that can be applied to the film in a controlled manner, allowing reactive species to be introduced after the film structure is already formed and sealed, thus avoiding direct exposure to air during the critical extrusion step.
3Ease of manufacture
If films are stored and transported as prefabricated items to simplify manufacturing, then ease of manufacture is improved, but plasticizers evaporate and reactive species degrade during storage
Solution Approach 1:
The patent performs the film extrusion and basic structure formation as a preliminary action that can be done in advance and stored. However, the critical steps of plasticizer infusion and reactive species incorporation are deferred to just before device assembly. This timing strategy allows the film to be stored in a stable, dry state without significant plasticizer loss or species degradation.
Solution Approach 2:
The patent changes the moisture content and plasticizer fraction parameters dynamically: the film is stored in a dry state (low moisture, minimal plasticizer) for stability during transport, then the plasticizer fraction is increased to optimal levels (40-60 wt%) only when the film is ready for device assembly. This parameter change optimizes both storage stability and final performance.
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 modified films exhibit enhanced ionic conductivity, up to 20% higher than prefabricated films, while maintaining mechanical integrity, suitable for use in electrochemical devices like electrochromic windows and batteries.
Implementation Method 1
exposing, for a treatment period and under treatment conditions, the prefabricated film to a solvent
Implementation Method 2
The solvent penetrates the film matrix, and the plasticizer distributes throughout the polymer structure
Implementation Method 3
removal of excess solvent
Data Source
AI summary
Methods of modifying a property of a prefabricated film are provided. The prefabricated film is exposed to a solvent to modify a property of the prefabricated film to provide a modified film. In some embodiments the solvent comprises a plasticizer. In some embodiments, the property comprises ionic conductivity. In some embodiments, the solvent is part of a solution comprising a reactive compound. In some embodiments, the reactive compound comprises an alkali metal salt.