Electrochromic Device Redox Element Charge Sequestration
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Solution Overview
Problem
Electrochromic devices face performance degradation due to faradaic losses, leading to changes in optical transmissivity and durability issues over time, especially affected by temperature, bias ranges, switching rates, and solar radiation exposure.
Innovation Solution
Incorporating a redox element within the electrochromic device that sequesters charge to mitigate faradaic losses, allowing the device to maintain optical properties by selectively oxidizing or reducing the redox element in response to electrical potentials, thereby compensating for spurious oxidation and reduction mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a conventional electrochromic device is operated over time, then the device can cycle between optically less and more transmissive states, but faradaic losses cause performance degradation and drift in optical transmissivity range
Solution Approach 1:
An auxiliary redox layer is introduced as an intermediary component between the primary electrochromic layers. This auxiliary layer acts as a charge buffer that absorbs faradaic losses through its own redox reactions, preventing these losses from directly affecting the optical performance of the main electrochromic materials. The auxiliary layer mediates the charge balance, allowing the device to maintain its optical transmissivity range over extended cycling lifetimes despite the presence of faradaic losses in the system.
2Adaptability or versatility
If the device operates under varying environmental conditions (temperature, solar radiation, bias ranges), then the device can function in different scenarios, but durability and performance stability deteriorate
Solution Approach 1:
The patent employs multiple redox layers with different redox potentials and characteristics, allowing the system to adapt to varying operational parameters such as temperature, bias ranges, and switching rates. By having multiple layers that can be selectively activated based on conditions, the device maintains durability across diverse environmental scenarios. The auxiliary redox layers provide additional charge storage capacity that compensates for accelerated degradation under harsh conditions like high temperature or intense solar radiation.
3Reliability
If faradaic losses occur through spurious oxidation mechanisms, then charge balance is disrupted, but the redox element can sequester charge to mitigate this
Solution Approach 1:
The auxiliary redox layers serve multiple functions simultaneously: they act as charge buffers to compensate for faradaic losses, provide additional charge storage capacity, and help maintain the charge balance across the electrochromic device. This multi-functionality allows the patent to address charge balance stability issues without proportionally increasing device complexity, as the auxiliary layers perform several critical functions within a single structural addition.
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 redox element effectively prevents performance degradation by maintaining the photopic ratio and optical transmissivity of the electrochromic device throughout its lifetime, ensuring consistent operation and extended durability.
Implementation Method 1
The redox element can be selectively oxidized or reduced in a redox reaction in response to an electrical potential applied to the electrochromic device
Implementation Method 2
one of which becomes optically less transmissive (e.g., takes on color) in its electrochemically oxidized state while the other becomes optically less transmissive (e.g., takes on color) in its electrochemically reduced state
Data Source
AI summary
An electrochromic multi-layer stack is provided. The multi-layer stack includes an electrochromic multi-layer stack having a first substrate, a first electrically conductive layer, a first electrode layer, an ion conductor layer, a second substrate, a second electrically conductive layer, and a second electrode layer. The multi-layer stack includes a redox element, wherein the redox element is electrically isolated from the first and second electrically conductive layers and the first and second electrode layer and is laterally adjacent to either the first electrically conductive layer and the first electrode, or the second electrically conductive layer and the second electrode layer. A method for controlling an electrochromic device is also provided.