High-Entropy Fluorite Oxide Composite for Stable Calcium Heat Storage
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Solution Overview
Problem
Existing calcium-based thermochemical heat storage materials suffer from degradation in cyclic stability due to high-temperature sintering and mechanical stress, leading to energy density decay and fragmentation, which affects their performance in solar thermal power plants.
Innovation Solution
A high-entropy fluorite oxide is modified with calcium oxide to form a porous foam-like structure, using zirconium, cerium, lanthanum, and ytterbium oxides as physical barriers to prevent calcium oxide crystal growth and enhance CO2 adsorption, dissociation, and migration, thereby improving cyclic stability and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If calcium oxide is used as heat storage material, then high theoretical energy density is achieved, but cyclic stability degrades due to high-temperature sintering
Solution Approach 1:
The patent creates a composite material system consisting of calcium oxide particles dispersed in a fluorite oxide matrix (formed by zirconium, cerium, lanthanum, neodymium, and ytterbium oxides). This composite structure allows the calcium oxide to maintain its high energy density for heat storage while the fluorite oxide matrix prevents sintering and degradation during cyclic operation, thus resolving the contradiction between energy density and cyclic stability
Solution Approach 2:
The fluorite oxide matrix is designed with a porous structure that physically separates calcium oxide particles, preventing them from sintering together at high temperatures. The porous structure maintains surface area and prevents particle aggregation, thereby preserving cyclic stability while allowing the calcium oxide to function effectively for heat storage
2Use of energy by moving object
If calcium-based medium is used in fluidized system, then heat storage function is achieved, but fragmentation and wear occur due to mechanical stress and thermal stress
Solution Approach 1:
The porous fluorite oxide matrix acts as a protective framework that mechanically supports calcium oxide particles during fluidized operation. This structure absorbs mechanical stress and prevents particle fragmentation, while the porous nature allows gas flow and maintains heat storage functionality
Solution Approach 2:
The composite structure of calcium oxide dispersed in fluorite oxide creates a more mechanically robust material system. The fluorite oxide matrix provides mechanical strength and resistance to wear, while the calcium oxide particles maintain the heat storage function, resolving the contradiction between heat storage capability and mechanical strength
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 modified material maintains high energy density and cyclic stability, suitable for large-scale applications by preventing sintering and enhancing CO2 adsorption capacity, making it suitable for solar thermal power plants.
Implementation Method 1
The oxides of zirconium and the four rare earth elements form XO2-type fluorite oxides, acting as physical barriers to prevent a growth and an aggregation of CaO crystals
Implementation Method 2
The material has a porous foam-like structure, with a large number of pores providing a large adsorption area for active CaO
Implementation Method 3
the fluorite structure promotes an adsorption, a dissociation, and a migration of CO2 on the material surface
Implementation Method 4
The XO2-type fluorite structure provides oxygen vacancies, promoting the adsorption, dissociation, and migration of CO2 during the adsorption/desorption reaction
Data Source
AI summary
The present invention provides a calcium-based thermochemical heat storage material modified with high-entropy fluorite oxide and a preparation method thereof. The material comprises a calcium-based material and a high-entropy fluorite oxide, with the calcium-based material accounting for 70-85% by mass. The calcium-based material is calcium oxide, and the high-entropy fluorite oxide is a fluorite-structured oxide formed by zirconium, cerium, lanthanum, neodymium, and ytterbium, with a molar ratio of 1:1:1:1:1 for the oxides of zirconium, cerium, lanthanum, neodymium, and ytterbium. The invention utilizes the high-entropy fluorite oxide as an anti-sintering component to disperse calcium oxide and prevent its sintering, while simultaneously promoting the adsorption, dissociation, and migration of CO2 on the surface of the material, thereby enhancing the cycling stability and energy density of the heat storage material.