Oriented Plate Crystal Thermoelectric Material via Calcium Cobaltite Template
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Solution Overview
Problem
Current methods for producing CoO2-based layered oxide thermoelectric conversion materials are not industrially effective, limiting their large-scale production and practical application.
Innovation Solution
A method involving the use of a plate crystal of calcium cobaltite as a template, combined with bismuth, cobalt, and calcium compounds, promotes crystal growth in the longitudinal direction during firing, resulting in a sintered product with oriented plate crystals, enhancing thermoelectric characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pressure sintering method is used to produce CoO2-based layered oxide thermoelectric conversion material, then the material exhibits excellent orientation and thermoelectric characteristics, but it is difficult to prepare sintered product in large amount at the same time and is not industrially effective
Solution Approach 1:
The patent uses plate crystals of calcium cobaltite as templates before the main sintering process. These pre-formed template crystals are mixed with raw materials and subjected to normal pressure sintering, which guides the growth of new crystals along the template structure, achieving excellent orientation without requiring pressure sintering equipment.
Solution Approach 2:
The plate crystals of calcium cobaltite serve as intermediary templates that mediate between the raw materials and the final thermoelectric conversion material. These templates provide a structured framework that directs crystal growth and ensures proper orientation during normal pressure sintering, replacing the need for complex pressure sintering equipment.
2Productivity
If normal pressure sintering method is used to produce thermoelectric conversion material, then it is industrially effective and can be produced in large amount, but the material does not exhibit excellent orientation and thermoelectric characteristics
Solution Approach 1:
The patent performs preliminary preparation of plate crystal templates from calcium cobaltite before the normal pressure sintering process. These pre-formed templates are then mixed with raw materials (bismuth compound, cobalt compound, calcium compound) and sintered at normal pressure, which enables the formation of well-oriented crystals without requiring complex pressure sintering equipment.
Solution Approach 2:
The plate crystals of calcium cobaltite act as intermediary templates that facilitate the formation of oriented crystals during normal pressure sintering. These templates provide a structural guide that ensures the final thermoelectric conversion material achieves excellent orientation and thermoelectric characteristics while being produced through simple normal pressure sintering suitable for industrial scale-up.
3Reliability
If plate crystal of CoO2-based layered oxide is used to achieve excellent thermoelectric characteristics, then the material exhibits favorable performance, but the production method is not industrially effective
Solution Approach 1:
The patent uses plate crystals of calcium cobaltite as intermediary templates to guide the formation of CoO2-based layered oxide crystals. These templates are mixed with raw materials and subjected to normal pressure sintering, which enables the production of well-oriented thermoelectric conversion material through a simple and industrially effective process.
Solution Approach 2:
The patent essentially copies the successful template structure of calcium cobaltite plate crystals to produce the desired CoO2-based layered oxide structure. By using the calcium cobaltite plate crystals as templates and allowing them to guide crystal growth during sintering, the method reproduces the excellent orientation and thermoelectric characteristics without requiring complex manufacturing processes.
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 method enables the production of CoO2-based layered oxide thermoelectric conversion materials with excellent thermoelectric characteristics in an industrially effective manner, comparable to those produced by pressure sintering, while allowing for larger-scale production.
Implementation Method 1
Thermoelectric conversion is an energy conversion method in which the Seebeck effect is utilized to impart the temperature difference between both ends of a thermoelectric conversion material, thereby generating the potential difference to conduct electricity generation.
Implementation Method 2
a method involving the use of a plate crystal of calcium cobaltite as a template, combined with bismuth, cobalt, and calcium compounds, promotes crystal growth in the longitudinal direction during firing, resulting in a sintered product with oriented plate crystals
Data Source
AI summary
There is provided a thermoelectric conversion material which is characterized by being composed of a sintered body of plate-like crystals of a composite oxide represented by general formula (2) BifCagM3hCoiM4jOk, and by having a density of 4.0-5.1 g/cm3. This thermoelectric conversion material is also characterized in that: when observed by SEM, the ratio of the plate-like crystals of a composite oxide represented by general formula (2) having an inclination in the major axis direction within 0±20° relative to the surface of the thermoelectric conversion material is 60% or more on the number basis; the average length of the lengths of the plate-like crystals of a composite oxide represented by general formula (2) is 20 μm or more; and the aspect ratio of the plate-like crystals of a composite oxide represented by general formula (2) is 20 or more.