Electrochromic Device Lithiation Through Top TCO Layer
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Solution Overview
Problem
Conventional electrochromic devices experience energy loss and reduced light transmission due to lithium up-diffusion into the top TCO layer during the lithiation process, leading to degraded optical properties and a narrower transmission range.
Innovation Solution
Lithiating the top electrochromic layer through the top TCO layer instead of directly lithiating the electrochromic layer, using techniques like sputtering or evaporation, and controlling temperature conditions to prevent lithium incorporation into the TCO layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the electrochromic layer is directly lithiated, then the lithiation process is simple and direct, but lithium up-diffusion into the top TCO layer occurs causing energy loss and degraded optical properties
Solution Approach 1:
The patent applies preliminary action by forming the complete multi-layer stack structure (substrate, TCO layers, electrochromic layer, ion conductor layer, counter electrode) before performing the lithiation process. This ensures that the top TCO layer is already in place to act as a barrier against lithium up-diffusion during subsequent lithiation of the electrochromic layer, preventing energy loss while maintaining manufacturing simplicity
Solution Approach 2:
The top TCO layer serves as an intermediary barrier between the lithiation process and the TCO layer itself. By having this intermediate layer in place before lithiation, it mediates the prevention of lithium up-diffusion, allowing the lithiation to proceed without causing energy loss or degrading optical properties
2Ease of manufacture
If the electrochromic layer is directly lithiated, then the process is straightforward, but the optical properties and transmission range are degraded
Solution Approach 1:
The complete multi-layer stack is formed in advance before lithiation, with the top TCO layer already positioned to protect against lithium up-diffusion. This preliminary structuring enables straightforward lithiation while preserving high optical transmission (60-80% in bleached state) and appropriate coloration properties
Solution Approach 2:
The top TCO layer acts as an intermediary protective barrier during lithiation, allowing the process to remain simple and straightforward while preventing degradation of optical properties. This intermediary layer ensures that lithium ions do not diffuse upward, maintaining the transmission range and color quality
3Productivity
If lithium is allowed to diffuse into the TCO layer, then the lithiation process is complete, but the bleached-state transmission is reduced
Solution Approach 1:
The multi-layer stack is fully constructed with the top TCO layer in place before initiating lithiation. This preliminary configuration allows the lithiation process to complete efficiently while the top TCO layer simultaneously prevents lithium up-diffusion, maintaining bleached-state transmission at 60-80%
Solution Approach 2:
The top TCO layer serves as an intermediary barrier that allows lithiation to proceed to completion while blocking lithium up-diffusion. This intermediary function ensures both process completion and preservation of high illumination transmission in the bleached state
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 method improves bleached-state transmission by 5-15% and optimizes the color and transmission range, particularly at visible light wavelengths, while maintaining the performance of the multi-layer electrochromic stack.
Implementation Method 1
lithium up-diffusion into the top TCO layer during the lithiation process
Implementation Method 2
using techniques like sputtering or evaporation
Implementation Method 3
using techniques like sputtering or evaporation
Data Source
AI summary
A method for lithiating an electrochromic device comprise forming a first transparent conductive layer on a substrate, forming an electrochromic structure on the first transparent conductive layer, forming a second transparent conductive layer on the electrochromic structure, and lithiating the electrochromic structure through the second transparent conductive layer. In one exemplary embodiment lithiating the electrochromic structure comprises lithiating the electrochromic structure at a temperature range of between about room temperature and about 500 C for the duration of the lithiation process. In another exemplary embodiment, lithiating the electrochromic structure further comprises lithiating the electrochromic structure by using at least one of sputtering, evaporation, laser ablation and exposure to a lithium salt. The electrochromic device can be configured in either a “forward” or a “reverse” stack configuration.