Cu2Se Thermoelectric Material Multi-Phase ZT Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thermoelectric materials exhibit low ZT values at temperatures lower than 600°C, making them unsuitable for thermoelectric power generation, as they fail to maintain high performance across a broad temperature range.
Innovation Solution
A thermoelectric material composed of Cu and Se with multiple crystal structures, including monoclinic and cubic structures, is developed, which maintains a high ZT value from 100°C to 600°C by transitioning between different crystal structures with temperature, enhancing thermoelectric conversion performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional thermoelectric materials (CuxSe with x≤2) are used, then high ZT value is achieved at high temperature (600-727°C), but ZT value becomes very low at low temperature (≤600°C)
Solution Approach 1:
The patent changes the compositional parameter x in CuxSe to be greater than 2 (specifically 2.01≤x≤2.1), which fundamentally alters the material's phase behavior and crystal structure. This compositional parameter change enables the material to maintain high ZT values across a broad temperature range from 100°C to 600°C, resolving the temperature-dependent performance instability of conventional materials.
Solution Approach 2:
The patent creates a composite crystal structure containing multiple phases (monoclinic Cu2Se, cubic Cu2Se, and Cu-rich phases) within the same material system. This multi-phase composite structure synergistically provides both low-temperature and high-temperature performance, achieving high ZT values across the entire 100-600°C range rather than optimizing for a single temperature regime.
2Reliability
If single crystal structure is used, then material simplicity is maintained, but thermoelectric conversion performance over broad temperature range is limited
Solution Approach 1:
The patent deliberately creates a composite material system with multiple crystal phases (monoclinic, cubic, and Cu-rich phases) coexisting in CuxSe with x>2. This multi-phase composite structure provides synergistic effects that enhance thermoelectric conversion performance across broad temperature ranges, accepting increased structural complexity as necessary for improved reliability.
Solution Approach 2:
The patent introduces local compositional variations within the material, specifically creating Cu-rich regions and Se-deficient regions distributed throughout the crystal structure. These local compositional differences create distinct phases with complementary properties, where each phase contributes optimally to thermoelectric performance at different temperature conditions.
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 low thermal diffusivity and high Seebeck coefficient, resulting in a significantly higher ZT value across the desired temperature range, improving thermoelectric conversion efficiency and stability for power generation applications.
Implementation Method 1
The thermoelectric conversion power generation is a method which generates power by converting thermal energy to electrical energy using a thermoelectromotive force generated by creating a temperature difference in a thermoelectric conversion element
Implementation Method 2
the thermoelectric conversion cooling is a method which produces cooling by converting electrical energy to thermal energy using an effect that a temperature difference creates between both ends of a thermoelectric conversion element when a direct current flows through the both ends of a thermoelectric conversion element
Data Source
AI summary
Disclosed is a thermoelectric conversion material having excellent performance. The thermoelectric material according to the present disclosure includes Cu and Se, and has a plurality of different crystal structures together, in which Cu atoms and Se atoms are arranged in the crystal, at a predetermined temperature.