AgSb1-xCdxTe2 P-Type Material for Lead-Free Thermoelectric Conversion
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Solution Overview
Problem
The challenge in thermoelectric research is to develop environment-friendly, high-performance materials for low- to mid-temperature thermoelectric applications, as lead-based chalcogenides are toxic and difficult to scale up, while single-crystalline SnSe has limited practical applicability.
Innovation Solution
A p-type material of Formula AgSb1-xCdxTe2 is developed, where x is in the range of 0.01-0.07, synthesized through a process involving precursor mixing, heating, and cooling, which enhances electrical conductivity and suppresses thermal conductivity via nanoscale superstructures formed by Cd doping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead-based chalcogenides (PbTe/PbSe/PbS) are used for thermoelectric power generation, then high thermoelectric performance is achieved, but environmental toxicity increases
Solution Approach 1:
The patent changes the chemical composition parameters by replacing toxic lead (Pb) with non-toxic elements (Ag, Sb, Te) in specific ratios defined by the formula AgSb1-xCdxTe2 where x ranges from 0.01 to 0.07. This parameter change maintains thermoelectric performance while eliminating environmental toxicity associated with lead-based materials.
Solution Approach 2:
The patent creates a composite material system combining silver (Ag), antimony (Sb), cadmium (Cd), and tellurium (Te) in a specific stoichiometric relationship. This composite approach allows the material to achieve high thermoelectric figure of merit (zT) values without relying on toxic lead, thus resolving the contradiction between performance and environmental safety.
2Reliability
If single crystal SnSe is used to achieve record high zT, then thermoelectric figure of merit is improved, but manufacturing complexity and scalability worsen
Solution Approach 1:
The patent changes the material state parameter from single crystal to polycrystalline form, which dramatically simplifies manufacturing while maintaining high thermoelectric performance through optimized compositional parameters (AgSb1-xCdxTe2 with x=0.01-0.07). This allows achievement of zT values comparable to single crystals through much more scalable polycrystalline processing.
Solution Approach 2:
The patent creates polycrystalline materials that replicate the high thermoelectric performance characteristics of single crystal SnSe through compositional optimization. Instead of requiring the complex single crystal structure, the patent uses a polycrystalline copy approach with AgSbTe2-based composition that achieves similar zT values through much simpler and more scalable manufacturing processes.
3Adaptability or versatility
If a single material is used to cover both low and mid-temperature regimes, then device versatility is improved, but material performance optimization worsens
Solution Approach 1:
The patent develops a universal material AgSb1-xCdxTe2 that functions effectively across both low-temperature (300-500K) and mid-temperature (500-800K) regimes. By optimizing the compositional parameter x within the range 0.01-0.07, the material achieves high thermoelectric figure of merit throughout this broad temperature range, eliminating the need for different specialized materials for different temperature applications.
Solution Approach 2:
The patent uses compositional parameter optimization (varying x in AgSb1-xCdxTe2) to tune the thermoelectric properties across a broad temperature range. This parameter change approach allows a single material composition to maintain high performance from 300K to 800K, achieving both versatility and optimized performance simultaneously.
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 record-high thermoelectric figure of merit (zT) of 2.6 at 573 K and a device figure of merit (ZTdev) of ~1.9 over 300-600 K, outperforming existing p-type materials, with a single material covering both low and mid-temperature regimes.
Implementation Method 1
thermoelectric (TE) energy conversion, wherein heat is converted directly into electricity using a class of materials known as thermoelectric materials
Implementation Method 2
heating the first mixture at a first temperature followed by heating at a second temperature to obtain a melt
Data Source
AI summary
The present disclosure discloses a p-type material of Formula I: AgSb1-xCdxTe2, wherein x is in a range of 0.01-0.07. It further discloses a process of preparation of the p-type material, and the use of the p-type material as a thermoelectric material.