Low-Oxygen MAX Precursor via Ball Milling
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Solution Overview
Problem
The high cost of producing MXene due to the expensive transition metals used in its manufacturing process, which accounts for 80% of the total manufacturing cost, necessitates a method to reduce production costs while maintaining high quality.
Innovation Solution
A method involving the application of a physical force, such as milling, to a mixture of low-grade metal oxide and a nitrogen or carbon source, followed by heat-treatment to produce metal nitride or carbide, and subsequent synthesis with aluminum or silicon to create a MAX precursor. This precursor is then reacted with an acid-based solution to produce MXene with reduced oxygen content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low-grade metal oxide is used as raw material, then production cost is reduced, but oxygen content in MAX precursor increases
Solution Approach 1:
The patent applies preliminary action by performing high-energy ball milling before heat treatment to reduce crystal grain size of low-grade metal oxide to 3-50 nm. This pre-processing step increases reactivity and enables thorough oxygen removal during subsequent heat treatment, allowing the use of low-grade materials while achieving low oxygen content in the final product
Solution Approach 2:
The patent changes physical parameters by reducing crystal grain size to nanometer scale (3-50 nm) through ball milling, and by optimizing heat treatment temperature (1100-1400°C) and time (1-5 hours). These parameter changes enable effective oxygen removal from low-grade metal oxides, resolving the contradiction between using cheap raw materials and achieving low oxygen content
2Object-affected harmful factors
If high-energy ball milling is applied to reduce crystal grain size, then oxygen content is reduced, but energy consumption and processing time increase
Solution Approach 1:
The patent optimizes the ball milling process by controlling crystal grain size to a specific range (3-50 nm) rather than continuously reducing it. This parameter optimization achieves sufficient oxygen removal while avoiding excessive energy consumption that would result from prolonged milling or overly fine grain sizes
Solution Approach 2:
The patent combines ball milling with subsequent heat treatment in a continuous process flow. The ball milling prepares the material by reducing grain size, and the heat treatment immediately follows to remove oxygen. This continuous process maximizes the effectiveness of each step while minimizing total energy consumption and processing time
3Object-affected harmful factors
If heat treatment temperature is increased to reduce oxygen content, then oxygen removal is improved, but energy consumption and risk of material degradation increase
Solution Approach 1:
The patent optimizes heat treatment temperature to a specific range (1100-1400°C) based on the nanometer-scale crystal grain size achieved through ball milling. This optimized temperature range is lower than conventional heat treatment temperatures because the pre-reduced grain size increases reactivity, enabling effective oxygen removal at moderate temperatures and thus reducing energy consumption
Solution Approach 2:
The patent performs ball milling to reduce crystal grain size before heat treatment. This preliminary action prepares the material by creating highly reactive nanometer-scale particles, which then require lower heat treatment temperatures and shorter times for effective oxygen removal, thereby reducing overall energy consumption and avoiding material degradation
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 significantly reduces the oxygen content in MAX precursors and MXene, thereby improving their electrical conductivity and electromagnetic shielding performance, while also lowering production costs by utilizing low-grade metal oxides.
Implementation Method 1
The physical force may be applied through milling. Through the milling, the mixture may be crushed to increase a surface area of the mixture. By the milling, a crystal grain size of the carbon source may be reduced to 3 nm to 50 nm, and a crystal grain size of the low-grade metal oxide may be reduced to 3 to 50 nm.
Implementation Method 2
heat-treating the mixture to prepare metal nitride or metal carbide. The heat-treating may be performed at 1100° C. to 1400° C.
Implementation Method 3
manufacturing MXene by reacting a MAX precursor manufactured according to the above-described method with an acid-based solution. The acid-based solution may include one or more selected from among hydrofluoric acid (HF), LiHF2, NaHF2, KHF2, lithium fluoride (LiF), sodium fluoride (NaF), magnesium fluoride (MgF2), strontium fluoride (SrF2), beryllium fluoride (BeF2), calcium fluoride (CaF2), ammonium fluoride (NH4F), ammonium difluoride (NH4HF2), and ammonium hexafluoroaluminate ((NH4)3AlF6).
Data Source
AI summary
The present invention pertains to a MAX precursor having a reduced oxygen content, and a method for producing MXene. A method for producing a MAX precursor according to the present invention comprises the steps of: applying a physical force to a mixture of a lower metal oxide and at least one among a nitrogen source and a carbon source; heat-treating the mixture to prepare a metal nitride or metal carbide; and synthesizing the metal nitride or metal carbide with aluminum or silicon to produce the MAX precursor.