MXene-Modified Thermoelectric Composite Grain Boundary Engineering
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Solution Overview
Problem
Current thermoelectric materials, particularly sintered materials, face challenges with low electrical conductivity and reliability due to electron scattering at crystal grain boundaries and element volatilization, limiting their thermoelectric ability and durability.
Innovation Solution
Incorporating MXene, a two-dimensional inorganic compound, at the boundaries of crystal grains within a thermoelectric material to form a composite material, which increases electrical conductivity and reduces thermal conductivity, while improving mechanical properties through a core-shell structure or dispersion in a conductive polymer matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sintered material is used instead of single-crystalline material, then reliability and durability are improved, but electrical conductivity and thermoelectric ability decrease
Solution Approach 1:
The patent applies local quality by selectively modifying only the crystal grain boundary regions with MXene coating, while keeping the interior of crystal grains as the original thermoelectric material. This localized modification reduces electron scattering at boundaries without altering the bulk material properties, thereby improving reliability while maintaining electrical conductivity.
Solution Approach 2:
The patent creates a composite material structure where MXene (a two-dimensional transition metal carbide or nitride) is combined with traditional thermoelectric materials like Bi2Te3. The MXene forms a core-shell structure or dispersed phase at grain boundaries, creating a composite that leverages the high reliability of sintered materials while MXene's high electrical conductivity compensates for the conductivity loss at boundaries.
2Power
If MXene is added to improve electrical conductivity, then thermoelectric ability increases, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-coating the thermoelectric material powder with MXene before the sintering process. The powder coating step is performed beforehand, allowing the MXene to be uniformly distributed on particle surfaces before densification. This preliminary preparation simplifies the overall manufacturing compared to post-processing methods.
Solution Approach 2:
The patent utilizes parameter changes in the sintering process (temperature, pressure, atmosphere) to control the final distribution and morphology of MXene. By optimizing sintering parameters, the complex task of MXene integration is simplified, as the sintering process itself facilitates the formation of the desired core-shell or dispersed structure without requiring additional complex processing steps.
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 integration of MXene enhances the thermoelectric ability and mechanical properties of the material, increasing the ZT figure of merit by up to 40% and improving reliability, making it suitable for various temperature range applications.
Implementation Method 1
electrical conductivity decrease due to electron scattering generated at a boundary of a crystal grain
Implementation Method 2
MXene inserted at a boundary of a crystal grain consisting of a thermoelectric material
Implementation Method 3
Seebeck effect, which may be used for thermoelectric generation
Implementation Method 4
Peltier effect, which may be used for electronic refrigeration
Data Source
AI summary
Disclosed is a thermoelectric composite material includes a thermoelectric material including crystal grains; and a MXene inserted at boundaries of the crystal grains consisting of the thermoelectric material. Accordingly, the thermoelectric composite material may have a reduced thermal conductivity and an increased electrical conductivity. Furthermore, mechanical properties of the thermoelectric composite material may be improved. Thus, the thermoelectric composite material may improve the thermoelectric ability of a thermoelectric module including the same. A method of manufacturing the thermoelectric composite material includes coating MXene on a surface of a thermoelectric material powder including crystal grains; and sintering the thermoelectric material powder coated with the MXene to form a sintered body including the MXene inserted at boundaries of the crystal grains consisting of the thermoelectric material.