Lithium Nickel Oxide Electrode Electrochemical Formatting for Adhesion
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Solution Overview
Problem
Lithium nickel oxide electrodes used in electrochromic devices face issues of instability due to coexistence of Ni2+ and Ni3+ ions, leading to incomplete oxidation or reduction, narrow electrochromic range, and poor adhesion on conductive substrates, resulting in slow coloring-decoloring speeds and potential separation from the electrode surface.
Innovation Solution
Electrochemical formatting of the lithium nickel oxide layer before device assembly to achieve a single oxidation number for nickel, ensuring complete oxidation-reduction and improved adhesion, using oxidative and reductive voltages in an electrochemical cell with a suitable electrolyte, and optional heat-treatment for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium nickel oxide is prepared by conventional methods (sol-gel, sputtering, pulse laser deposition), then the material can be deposited on conductive substrates, but the electrode exhibits poor adhesion and instability due to coexistence of Ni2+ and Ni3+ ions
Solution Approach 1:
The patent applies preliminary electrochemical formatting treatment to the lithium nickel oxide layer before the electrochromic device is assembled and before repeated oxidation-reduction cycles begin. This preliminary action converts mixed Ni2+/Ni3+ states to a uniform Ni3+ state, preventing subsequent adhesion problems and improving electrode stability throughout the device lifetime.
Solution Approach 2:
The patent changes the oxidation state parameter of nickel ions from a mixed state (Ni2+ and Ni3+) to a uniform state (Ni3+) through controlled electrochemical formatting. This parameter change eliminates the instability caused by coexisting oxidation states and improves overall electrode reliability.
2Productivity
If lithium nickel oxide contains mixed Ni2+ and Ni3+ ions, then the material can be deposited, but the coloring-decoloring speed becomes slow due to incomplete oxidation-reduction
Solution Approach 1:
The electrochemical formatting is performed as a preliminary step before device operation, establishing complete oxidation-reduction capability in advance. This ensures that during normal electrochromic operation, the uniform Ni3+ state enables fast and complete coloring-decoloring cycles without the delays caused by incomplete reactions.
3Strength
If lithium nickel oxide is deposited by sputtering method, then the layer can be formed, but adhesion to FTO glass becomes poor causing separation and air bubble generation
Solution Approach 1:
The electrochemical formatting treatment is applied as a preliminary step to convert Ni2+ ions to Ni3+ ions before the electrode undergoes repeated oxidation-reduction cycles during device operation. This preliminary conversion prevents the formation of NiOx or NiOOH that would cause adhesion failure, thereby maintaining strong adhesion to the FTO glass substrate throughout the device lifetime.
4Adaptability or versatility
If conventional electrochromic materials are used, then the device can operate, but the electrochromic range becomes narrow and optical properties are not very good
Solution Approach 1:
The patent changes the oxidation state parameter of nickel from mixed (Ni2+/Ni3+) to uniform (Ni3+), which expands the electrochromic range and improves optical properties. The uniform Ni3+ state enables broader wavelength modulation and better optical transmittance control across the electrochromic spectrum.
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 ensures complete decolorization regardless of electrode thickness, enhances electrochromic properties, and improves adhesion, resulting in a stable and efficient electrochromic device with wider optical range and reduced production costs.
Implementation Method 1
Electrochemical formatting of the lithium nickel oxide layer before device assembly to achieve a single oxidation number for nickel, ensuring complete oxidation-reduction
Implementation Method 2
Electrochromism means the phenomenon by which color changes according to a potential difference of an applied electric field
Implementation Method 3
optional heat-treatment for enhanced stability
Data Source
Figure 1~2
AI summary
The present invention provides A method for preparing an electrode containing lithium nickel oxide wherein nickel has a single oxidation number, which comprises the following steps: a) preparing an electrode containing the lithium nickel oxide (LixNi1-yO, 0.4<x<1, 0<y<1) layer formed on the conductive substrate; and b) applying oxidative voltage to the electrode, and then applying reductive votage thereto, an electrode prepared by the method and an electrochromic device containing the same. The electrode containing the lithium nickel oxide layer of the present invention exhibits wider optical electrochromic range and fast reaction speed, so that it can contribute to improving electrochromism and other optical properties of an electrochromic device.