MXene Two-Dimensional Particles for Humidity-Stable Conductive Films
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Solution Overview
Problem
MXene materials face conductivity issues under high humidity conditions due to incomplete Li removal, residual TMAOH, and multilayer structure, leading to low reliability and difficulty in forming conductive films.
Innovation Solution
A two-dimensional particle with a specific composition and production method involving etching, washing, intercalation with Na or K, and delamination to produce a conductive film with high conductivity, low Li content, and optimized particle size and thickness, ensuring stability under high humidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Li is used for intercalation to enhance conductivity, then conductivity is improved, but Li remains incompletely removed causing conductivity decrease under high humidity conditions
Solution Approach 1:
The patent extracts Li cations from the MXene interlayer space through systematic washing with water and uses Na or K cations as substitutes. The washing process removes residual LiCl and incompletely removed Li, while the substitute cations maintain the interlayer spacing and conductivity. This extraction approach resolves the contradiction by completely removing harmful Li while preserving the beneficial intercalation effect.
Solution Approach 2:
The patent changes the chemical composition parameter by substituting Li cations with Na or K cations. This parameter change maintains the intercalation effect (improving conductivity) while eliminating the humidity sensitivity issue (improving reliability). The substitute cations have different ionic radii and hydration properties that prevent the conductivity decrease observed with Li under high humidity conditions.
2Reliability
If TMAOH is used for delamination treatment, then delamination is achieved, but residual TMAOH remains causing low conductivity and moisture absorption
Solution Approach 1:
The patent extracts residual TMAOH from the MXene structure through extensive washing with water. The washing steps remove TMAOH and its decomposition products while preserving the MXene structure and intercalated cations. This extraction eliminates the harmful residual base that causes low conductivity and moisture absorption, while maintaining the delamination benefits.
Solution Approach 2:
The patent converts the harmful effect of TMAOH residual into a beneficial process by using the washing steps to not only remove TMAOH but also to control the interlayer spacing and stabilize the MXene structure. The washing process that removes harmful residues also optimizes the particle morphology and conductivity.
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 solution enables the formation of a conductive film with a conductivity of 2,000 S/cm or more, maintaining high performance even under high humidity conditions and avoiding the limitations of previous MXene technologies.
Implementation Method 1
removing at least a part of A atoms from the precursor using an etching liquid to produce an etched product
Implementation Method 2
mixing the water washed product with a metal-containing compound to produce an intercalated product, wherein the metal-containing compound comprises at least one metal selected from the group consisting of Na and K
Data Source
AI summary
A two-dimensional particle including: one or plural layers, the one or plural layers having a layer body represented by: MmXn, wherein M is at least one metal of Group 3, 4, 5, 6, or 7, X is a carbon atom, a nitrogen atom, or a combination thereof, n is 1 to 4, m is more than n but not more than 5, and a modifier or terminal T existing on a surface of the layer body, wherein T is at least one selected from a hydroxyl group, an amine group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom and a hydrogen atom; a metal cation is at least one cation selected from Na and K, and a content of Li in the two-dimensional particle is less than 0.002% by mass.