Conductive MXene Particles With Low Halogen and Large Flake Size
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Solution Overview
Problem
Current MXene materials used in electrical devices have low conductivity and contain high levels of chlorine and bromine, making them unsuitable for halogen-free applications, and existing delamination methods result in small two-dimensional particle sizes leading to low conductivity films.
Innovation Solution
A conductive two-dimensional particle with a total content of chlorine and bromine at 1,500 ppm or less is produced using a method involving etching and intercalation treatments with monovalent metal ions and organic compounds, resulting in a highly conductive film without the use of binders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional delamination methods (handshaking with TMAOH and ultrasonic treatment with DMSO) are used to obtain single-layer/few-layer MXene, then the material can be delaminated into individual layers, but the total content of chlorine and bromine becomes high and the two-dimensional particle size becomes small, resulting in low conductivity
Solution Approach 1:
The invention changes the chemical composition parameters by replacing conventional etching agents (HF, HCl) with non-halogen etching agents (formic acid, acetic acid, phosphoric acid). This parameter change eliminates chlorine and bromine contamination while maintaining the etching effectiveness needed for delamination, thereby resolving the contradiction between achieving delamination and avoiding halogen contamination
Solution Approach 2:
The invention introduces an intermediary substance (polymer binder such as polyvinylidene fluoride or polyacrylonitrile) that mediates between the MXene particles during film formation. This intermediary enables the formation of highly conductive films without requiring ultrasonic treatment, thereby preventing particle size reduction and halogen contamination while maintaining film conductivity
2Reliability
If ultrasonic treatment is performed to delaminate multilayer MXene, then the material can be separated into single-layer/few-layer particles, but the two-dimensional particle size becomes small leading to low conductivity films
Solution Approach 1:
The invention introduces a polymer binder as an intermediary that facilitates delamination through chemical interaction rather than mechanical ultrasonic treatment. The polymer binds to the MXene surface and enables layer separation through swelling and osmotic pressure effects, preserving the original particle size while achieving delamination, thus resolving the contradiction between delamination and particle size maintenance
Solution Approach 2:
The invention replaces the mechanical ultrasonic treatment system with a chemical delamination system using polymer binders and non-halogen etching agents. This substitution eliminates the mechanical shear forces that reduce particle size while achieving effective delamination through chemical mechanisms, thereby resolving the contradiction between delamination and particle size preservation
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 method achieves a conductivity of 2,000 S/cm or more in the formed film, suitable for halogen-free applications, with large two-dimensional particle sizes and minimal residual organic compounds, enhancing the material's performance and applicability.
Implementation Method 1
etching a predetermined precursor
Implementation Method 2
performing intercalation treatment of a monovalent metal ion
Implementation Method 3
performing intercalation treatment of an organic compound
Data Source
AI summary
A conductive two-dimensional particle of a layered material comprising one layer or one layer and plural layers, wherein the layer includes a layer body represented by: MmXn, and a modifier or terminal T exists on a surface of the layer body, wherein T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, or a hydrogen atom; and a monovalent metal ion, wherein the conductive two-dimensional particle does not contain an amine, a total content of chlorine and bromine in the conductive two-dimensional particle is 1,500 ppm by mass or less, and an average value of a major diameter of a two-dimensional surface of the conductive two-dimensional particle is 1.0 μm to 20 μm.