Electrochromic Working Electrode with Embedded Metal Complexes
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Solution Overview
Problem
Electrochromic cells with metal complex compounds used in electrochromic windows and e-paper face stability issues at elevated temperatures, as the working electrode's metal chelate complex dissolves in the electrolyte, leading to reduced switching stability and color change fidelity.
Innovation Solution
A working electrode material is developed comprising metal complex compounds embedded in a transparent matrix with hydroxy groups and organically polymerizable C=C double bonds, enhancing adhesion and preventing dissolution, thus maintaining stability and color change reliability even at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal complex compounds are used as working electrode material in electrochromic cells, then good optical and electrochemical properties are achieved, but the material dissolves in electrolyte at elevated temperatures leading to reduced stability
Solution Approach 1:
The patent embeds metal complex compounds (such as Fe-MEPE) into an organically modified silica polycondensate matrix to form a composite material. This composite structure prevents the metal complex compounds from dissolving in the electrolyte while maintaining their electrochromic properties. The silica matrix acts as a stable host that anchors the metal complexes, solving the dissolution problem at elevated temperatures.
2Ease of manufacture
If metal complex compounds are dissolved in solution for electrode preparation, then easy manufacturing is achieved, but poor adhesion and dissolution in electrolyte occur
Solution Approach 1:
The patent changes the physical state of the metal complex compound from dissolved solution to embedded solid within the silica matrix. This parameter change maintains ease of manufacture through solution-based coating processes while fundamentally improving adhesion stability by anchoring the metal complexes in the crosslinked silica network, preventing both dissolution and delamination.
3Adaptability or versatility
If electrochromic cells operate at elevated temperatures, then expanded operating range is achieved, but color change fidelity and switching stability deteriorate
Solution Approach 1:
The silica-embedded composite structure provides thermal stability that allows the electrochromic cell to operate at elevated temperatures without deteriorating color change fidelity. The rigid silica matrix maintains the structural integrity of the metal complex compounds, preventing thermal degradation and maintaining consistent optical switching performance across a broader temperature range.
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 embedded metal complex compounds in the electrochromic cell exhibit improved adhesion and stability, allowing for stable switching over thousands of cycles without significant color change degradation, even at temperatures above 60°C, and maintain high optical and electrochemical properties.
Implementation Method 1
at least one metal complex compound which is capable of entering into a redox reaction, with the transition from the oxidized to the reduced state and vice versa being accompanied by a deepening or weakening of the color
Implementation Method 2
The embedding material has units which are substituted with at least one hydroxy group and at least one substituent, which in turn has at least one organically polymerizable C=C double bond
Implementation Method 3
at least one substituent, which in turn has at least one organically polymerizable C=C double bond
Data Source
AI summary
The present invention relates to a material for the working electrode of an electrochromic cell, comprising: - a metal complex compound capable of undergoing a redox reaction, wherein the transition from the oxidized to the reduced state is accompanied by a deepening of the color and the transition from the reduced to the oxidized state by a corresponding dilution of the color, and - an embedding material comprising hydroxyl groups and non-aromatic, organically polymerizable C=C double bonds, wherein the embedding material preferably consists of at least 70 wt.%, based on the total embedding material, of an organic material and/or of a silica (hetero)polycondensate.The invention further relates to an electrochromic cell comprising: - a first substrate provided with a conductive coating, - a second, transparent substrate provided with a conductive coating, - a working electrode in contact with the conductive coating of one of these two substrates, and - an electrolyte material located between the working electrode and the other of these two substrates and containing mobile cations in the form of a dissociable metal salt, wherein the working electrode consists of or comprises the material as defined above.