Electrochromic Layer Monovalent Cation Insertion for Durability
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Solution Overview
Problem
Conventional electrochromic devices face durability issues due to the need for an initialization operation that involves high overvoltage, leading to electrode and electrochromic layer deterioration, especially when using gel polymer electrolytes which have lower ion content compared to liquid electrolytes.
Innovation Solution
A method where monovalent cations are inserted into the electrochromic layer using thermal evaporation deposition before adding the electrolyte layer, allowing the electrochromic layer to be colored and matching its state with the ion storage layer, thus eliminating the need for initialization and improving durability by ensuring high transmittance and preventing electrode damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an initialization operation is performed by applying high voltage to decolorize the ion storage layer, then the device can be driven, but the electrode layer and electrochromic layer deteriorate due to overvoltage
Solution Approach 1:
The patent applies preliminary action by inserting monovalent cations into the electrochromic layer before assembling the complete device. This pre-insertion of cations ensures that the electrochromic layer starts in a colored state that matches the ion storage layer, eliminating the need for high-voltage initialization operation that would otherwise cause overvoltage damage to the electrode and electrochromic layers.
2Device complexity
If gel polymer electrolyte is used instead of liquid electrolyte, then the device structure is simplified, but the amount of electrolytic ions is reduced requiring higher overvoltage
Solution Approach 1:
The patent compensates for the reduced ion amount in gel polymer electrolyte by performing preliminary action - inserting monovalent cations into the electrochromic layer before device assembly. This ensures sufficient ions are available in the electrochromic layer without requiring high overvoltage, thus maintaining durability while using the simpler gel polymer electrolyte structure.
3Ease of operation
If the electrochromic layer and ion storage layer are in mismatched states before driving, then initialization operation is required, but this causes electrode and electrochromic layer deterioration
Solution Approach 1:
The patent ensures the electrochromic layer and ion storage layer are in matched colored states through preliminary action - inserting monovalent cations into the electrochromic layer before assembly. This eliminates the need for initialization operation entirely, thereby preventing overvoltage damage to the electrode and electrochromic layers while maintaining ease of operation.
4Reliability
If thermal evaporation deposition is used to insert monovalent cations, then high transmittance is maintained and initialization is eliminated, but additional manufacturing steps are required
Solution Approach 1:
The patent replaces the conventional electrical initialization method with a physical vapor deposition process. By using thermal evaporation deposition to insert monovalent cations, the method eliminates the need for high-voltage electrical initialization, thereby preventing overvoltage damage while maintaining high transmittance. The vapor deposition process is integrated into the manufacturing sequence, making the additional step compatible with existing production workflows.
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
This approach enhances the driving durability of electrochromic devices by maintaining high transmittance and preventing electrode deterioration, while allowing for continuous manufacturing processes like roll-to-roll methods, improving both processability and productivity.
Implementation Method 1
a step of inserting monovalent cations into the electrochromic layer before placing the electrolyte layer on the electrochromic layer
Implementation Method 2
The electrochromic layer may contain WO 3 which is transparent in itself but is colored blue upon reductive reaction
Implementation Method 3
Electrochromism refers to a phenomenon in which an optical property of an electrochromic material is changed by an electrochemical oxidation or reduction reaction
Data Source
AI summary
The present application relates to a method for preparing an electrochromic device. In the preparation method of the present application, the device is prepared by inserting monovalent cations into a reducing electrochromic layer in advance through a dry process and laminating the colored electrochromic layer, an electrolyte layer and an oxidizing discoloring material-containing ion storage layer which is in a colored state in itself. Accordingly, the present application can improve driving durability of the electrochromic device.