Sunlight-activated phase change materials for controlled heat storage and triggered release
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Solution Overview
Problem
Current molecular solar thermal storage systems face challenges due to low energy storage density and the requirement for strong UV irradiation for E-to-Z switching, limiting their practical application in thermal energy storage and release.
Innovation Solution
Development of ortho-substituted azobenzene derivatives with red-shifted n-π* absorption, allowing for efficient E-to-Z switching under visible light, facilitating simultaneous phase transition and energy storage via the incorporation of aliphatic groups, enabling sunlight-activated phase change materials that store latent heat and photon energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If common MOST compounds like azobenzene derivatives are used, then the system can store photon energy in constrained chemical bonds, but the energy storage density remains low (around -41 kJ/mol)
Solution Approach 1:
The patent modifies the molecular structure of azobenzene derivatives by introducing ortho-substituents (fluorine, chlorine, bromine atoms) and varying alkyl chain lengths to optimize the energy storage density. These parameter changes in molecular composition and structure enable the material to achieve higher energy storage density while maintaining stability
Solution Approach 2:
The invention creates composite molecular structures combining azobenzene core with various functional groups (carboxylic acid, ester, amide) and alkyl chains. This composite approach allows simultaneous optimization of energy storage density, photostability, and thermal properties for practical applications
2Power
If strong UV irradiation is used for E-to-Z switching, then the photo-isomerization can be efficiently activated, but the requirement for UV light limits practical application under sunlight
Solution Approach 1:
The patent systematically modifies the absorption spectrum of azobenzene derivatives by introducing ortho-substituents that cause red-shift of the n-π* transition. This parameter change in optical properties enables the material to be activated by visible light and filtered sunlight instead of requiring strong UV irradiation, thereby achieving both efficient photo-isomerization and sunlight compatibility
Solution Approach 2:
The invention utilizes readily available sunlight as the energy source instead of requiring specialized UV light sources. By designing materials that can be activated by the abundant visible light component of sunlight, the system becomes more practical and economical for real-world energy storage applications
3Use of energy by moving object
If ortho-substituted azobenzene derivatives with red-shifted n-π* absorption are developed, then efficient E-to-Z switching under visible light is achieved, but the complexity of material synthesis increases
Solution Approach 1:
The patent employs modular synthesis approaches where the azobenzene core is first synthesized, then functional groups and alkyl chains are systematically added in separate steps. This segmentation of the synthesis process makes the complex ortho-substituted derivatives more manageable and scalable for production
Solution Approach 2:
The invention establishes structure-activity relationships that guide the selection of substituents and their positions, allowing optimization of visible light activation efficiency while controlling synthesis complexity through systematic variation of molecular parameters
4Quantity of substance
If aliphatic groups are incorporated to enable simultaneous phase transition, then latent heat and photon energy can be stored, but the material design complexity increases
Solution Approach 1:
The patent merges two energy storage mechanisms into a single material system: photon energy storage through photo-isomerization and latent heat storage through phase transition. The aliphatic side chains are specifically designed to facilitate phase transition at appropriate temperatures, enabling simultaneous dual-mode energy storage in one material
Solution Approach 2:
The invention creates multi-functional materials where the same molecular structure performs multiple functions: the azobenzene core handles photo-isomerization for photon energy storage, while the aliphatic groups enable phase transition for latent heat storage. This multi-functionality increases total energy storage capacity without requiring separate systems
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 new materials achieve high conversion rates of E-to-Z isomers under filtered sunlight, exhibiting exceptional stability and prolonged heat storage time, with energy release triggered by specific optical stimulation, enhancing solar energy harvesting capabilities.
Implementation Method 1
Photo-induced molecular transformations, either photo-chemical reactions or reversible photo-mechanical isomerizations, have attracted a significant attention as a potential chemical method for harnessing solar energy
Implementation Method 2
Development of ortho-substituted azobenzene derivatives with red-shifted n-π* absorption, allowing for efficient E-to-Z switching under visible light
Implementation Method 3
the capability of isomerizing in condensed phases (i.e. solid and liquid), and recyclability are unique characteristics of the MOST systems
Implementation Method 4
enabling sunlight-activated phase change materials that store latent heat and photon energy
Implementation Method 5
release the energy upon triggering in the form of heat
Data Source
AI summary
The present invention relates to a compound of Formula (I) where (II), (III), R1, R2, R3, R4, R5, Q, and Z are as described herein and compositions containing this compound. The present invention also relates to a methods of making a compound of Formula (I) and methods of using one or more of these compounds as a thermal-storage material thermal-storage device and. Methods of storing energy are also described.