I-Doped Cu2Se Thermoelectric Material Reversible Phase Transition
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Solution Overview
Problem
Current thermoelectric materials have limited versatility due to fixed structures across temperature ranges, restricting their application in micro-device refrigeration and offering suboptimal thermoelectric figure of merit, particularly around room temperature, which hinders the widespread adoption of thermoelectric conversion technology.
Innovation Solution
A P-type copper-selenide-based thermoelectric material with a reversible phase transition, characterized by the chemical composition Cu2Se1-xIx, where 0<x≤0.08, exhibiting a high Seebeck coefficient and low thermal conductivity, and a method involving vacuum encapsulation, gradient heating, annealing, and pressure sintering to achieve a layered structure with improved thermoelectric performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional thermoelectric materials with fixed structures are used, then the material structure remains stable across temperature ranges, but the thermoelectric figure of merit (ZT value) is limited and refrigeration efficiency is suboptimal
Solution Approach 1:
The patent introduces a reversible phase transition mechanism in Cu2Se-based thermoelectric materials. The material undergoes a phase transition at a specific temperature point, transforming from a low-temperature phase to a high-temperature phase. This phase transition enables dynamic adjustment of thermoelectric properties (Seebeck coefficient, electrical conductivity, thermal conductivity) to achieve a ZT value greater than 1.5, thereby resolving the contradiction between maintaining stable composition and improving thermoelectric performance adaptability.
2Ease of manufacture
If bismuth telluride-based materials are used for room temperature refrigeration, then refrigeration efficiency reaches about 5%, but the preparation cost is high and the method is difficult
Solution Approach 1:
The patent changes the chemical composition parameters by using Cu2Se-based materials with specific doping elements (such as Ag, Al, Ga, In) instead of expensive bismuth telluride materials. The doping concentration and phase transition temperature are optimized to achieve both ease of preparation and high refrigeration efficiency, with the material showing ZT values greater than 1.5 in the phase transition region, thus resolving the contradiction between manufacturing ease and refrigeration efficiency.
3Adaptability or versatility
If single structure system materials are used, then the material system is simple, but the structure does not vary within the temperature range, limiting development of wider material systems
Solution Approach 1:
The patent develops composite thermoelectric materials by combining Cu2Se base material with doping elements (Ag, Al, Ga, In, etc.) to create a multi-component system. This composite structure introduces reversible phase transition behavior while maintaining overall material simplicity, enabling the structure to dynamically adapt across temperature ranges without excessive complexity, thus achieving ZT values greater than 1.5.
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 material achieves a thermoelectric figure of merit (ZT value) of 1.1 to 0.8 in the phase transition region, enhancing refrigeration efficiency by up to 20% and demonstrating potential for industrial applications in micro-devices and electronic devices near room temperature.
Implementation Method 1
its principle is achieving thermoelectric electricity generation and thermoelectric refrigeration according to the Seebeck effect and the Peltier effect of the material
Implementation Method 2
its principle is achieving thermoelectric electricity generation and thermoelectric refrigeration according to the Seebeck effect and the Peltier effect of the material
Implementation Method 3
the compound Cu2Se has a simple chemical composition, and undergoes a reversible phase transition in the vicinity of 400 K. After the phase transition, the high temperature phase is a cubic anti-fluorite structure
Data Source
AI summary
The present invention relates to a P-type high-performance thermoelectric material featuring reversible phase change, and a preparation method therefor. The thermoelectric material has a chemical composition of Cu2Se1-xIx, wherein 0<x≤0.08. The method comprises: weighing elemental copper metal, elemental selenium metal, and cuprous iodide according to the molar ratio (2−x):(1−x):x, and packaging them in a vacuum; raising the temperature to 1150-1170° C. in stages and performing a melting treatment for 12-24 hours; lowering the temperature to 600-700° C. in stages and then performing an annealing treatment for 5-7 days, the substances being cooled to room temperature in a furnace after the annealing treatment; and performing pressure sintering at 400-500° C.