Indium-Doped SnTe Thermoelectric Material for High ZT Performance

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Solution Overview

Problem

Conventional thermoelectric materials have limited temperature range and strength of thermoelectric effect, making them unsuitable for wide industrial applications, particularly due to the use of lead-containing materials that pose environmental concerns.

Innovation Solution

A lead-free thermoelectric composition comprising tin (Sn), tellurium (Te), and indium (In) with specific doping levels, processed through ball-milling and hot-pressing to achieve high Seebeck coefficients and dimensionless figure of merit (ZT) values, enhancing thermoelectric performance at high temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lead-containing thermoelectric materials are used, then thermoelectric performance is improved, but environmental harm increases

Engineering Contradiction:

Improvethermoelectric performanceVSAvoidenvironmental harm

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes lead (Pb) from the thermoelectric material composition entirely, extracting the harmful element while maintaining the SnTe base structure. This is achieved by substituting lead with indium doping in the tin telluride lattice, eliminating environmental toxicity while preserving thermoelectric functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent modifies the compositional parameters of SnTe by introducing indium doping at specific concentrations (0.01-1.0 at.%). This parameter change transforms the material properties, achieving high Seebeck coefficients (≥50 μV/K) and ZT values (≥0.8) without lead, thus resolving the contradiction between performance and environmental safety.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional thermoelectric materials are used, then manufacturing simplicity is maintained, but temperature range limitation increases

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidtemperature range

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The patent employs ball-milling and hot-pressing processes to achieve fine-grained microstructures with specific grain size distributions. This parameter change in processing methodology enables the material to maintain structural integrity and thermoelectric performance across extended temperature ranges while keeping the manufacturing approach relatively simple and scalable.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If indium doping is increased to improve thermoelectric performance, then Seebeck coefficient increases, but material composition complexity increases

Engineering Contradiction:

ImproveSeebeck coefficientVSAvoidcomposition complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies indium doping at specific local concentrations within the SnTe lattice (0.01-1.0 at.% In), creating localized regions of enhanced thermoelectric properties. This local quality approach optimizes the Seebeck coefficient without requiring uniform high-level doping throughout the entire material, thus limiting composition complexity while achieving performance goals.

Inventive Principle:

Principle #3Local quality

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 indium-doped SnTe composition exhibits significantly improved thermoelectric properties, including high Seebeck coefficients and peak ZT values, while maintaining mechanical strength and reducing environmental impact by avoiding lead usage.

Implementation Method 1

ball-milling a plurality of components in a ball-milling vessel

Methodology Applied

Scientific EffectBall-milling:

Implementation Method 2

subsequently, mechanical-thermally processing the components

Methodology Applied

Scientific EffectHot-pressing:

Implementation Method 3

indium (In) with specific doping levels... Seebeck coefficient of the thermoelectric composition is at least about 50 μV/K

Methodology Applied

Scientific EffectDoping: Dopants

Data Source

PatentUS9905744B2Systems and methods for the synthesis of high thermoelectric performance doped-SnTe materials

Publication Date: 2018.02.27 MASSACHUSETTS INST OF TECH

AI summary

A thermoelectric composition comprising tin (Sn), tellurium (Te) and at least one dopant that comprises a peak dimensionless figure of merit (ZT) of 1.1 and a Seebeck coefficient of at least 50 μV/K and a method of manufacturing the thermoelectric composition. A plurality of components are disposed in a ball-milling vessel, wherein the plurality of components comprise tin (Sn), tellurium (Te), and at least one dopant such as indium (In). The components are subsequently mechanically and thermally processed, for example, by hot-pressing. In response to the mechanical-thermally processing, a thermoelectric composition is formed, wherein the thermoelectric composition comprises a dimensionless figure of merit (ZT) of the thermoelectric composition is at least 0.8, and wherein a Seebeck coefficient of the thermoelectric composition is at least 50 μV/K at any temperature.