High-efficiency thermochromic nano composite powder with core-shell structure and preparation method thereof

A nano-composite powder and thermochromic technology, which is applied in nanotechnology, nanotechnology, nano-optics, etc. for materials and surface science, can solve the problems of shortening the response time of phase change, poor thermal response, and phase change of thermochromic materials. High temperature and other problems, to achieve good application prospects, efficient use and control effect

Active Publication Date: 2018-10-16
GUANGZHOU INST OF ENERGY CONVERSION - CHINESE ACAD OF SCI +1
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to address existing VO 2 To address the problems of high phase transition temperature and poor thermal response of thermochromic materials, a high-efficiency thermochromic nanocomposite powder with core-shell structure and its preparation method are provided. The composite powder is based on VO 2 It is the core layer, and the tungsten bronze compound is the shell layer. Using the infrared absorption characteristics of tungsten bronze, the particle shell layer absorbs heat, and quickly transfers heat to the core layer VO through the closely connected core-shell structure. 2 Make it warm up and undergo a phase change, thereby increasing VO 2 The thermal response speed shortens the phase change response time and reduces the VO 2 Ambient temperature required for phase transition to occur

Method used

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  • High-efficiency thermochromic nano composite powder with core-shell structure and preparation method thereof

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Effect test

Embodiment 1

[0025] Take 5g A-phase VO with a particle size of 90nm 2 , added to a certain amount of water to prepare a mass concentration of 30% VO 2 Suspension, add 25g polyvinyl alcohol, mix and stir for 30min; add 0.5g ammonium tungstate and 0.015g ammonium chloride, mix and stir for 30min, so that the precursor of tungsten bronze adheres to VO 2 On the surface of the particles, 10g of citric acid was added, and the reaction was performed at a constant temperature of 80 °C for 1.5 hours to obtain a suspension. After centrifugal precipitation, vacuum drying at 100 °C was used to obtain VO coated with tungsten bronze precursor. 2 powder; put the obtained powder into a heating furnace, heat treatment at 400 ℃ for 2h, and obtain VO 2 @(NH 4 ) 0.1 WO 3 Core-shell structure nanocomposite powder, in which the core layer is VO 2 is the M / R phase, the shell (NH 4 ) 0.1 WO 3 The thickness is 20nm. prepared VO 2 @(NH 4 ) 0.1 WO 3 Core-shell structure nanocomposite powder can make VO ...

Embodiment 2

[0027] Take 5g of B-phase VO with a particle size of 20nm 2 , added to a certain amount of ethylene glycol to prepare a mass concentration of 1% VO 2 Suspension, add 2.5g polyethylene glycol, mix and stir for 30min; add 10g sodium tungstate and 1.5g sodium sulfate, mix and stir for 30min, make the precursor of tungsten bronze adhere to VO 2 Add 10g of oxalic acid to the surface of the particles, and react at a constant temperature of 180°C for 0.5h to obtain a suspension. After centrifugal precipitation, vacuum drying at 100°C gives VO 2 powder; put the obtained powder into a heating furnace, heat treatment at 600°C for 0.5h, and obtain VO 2 @Na 0.5 WO 3 Core-shell structure nanocomposite powder, in which the core layer VO 2 It is M / R phase, shell Na 0.5 WO 3 The thickness is 5nm. Prepared VO 2 @Na 0.5 WO 3 Core-shell nanocomposite powder can make VO 2 shortens the phase transition reaction time by 3 minutes.

Embodiment 3

[0029] Take 5g of M / R phase VO with a particle size of 70nm 2 , added to a certain amount of ethanol to prepare a mass concentration of 10% VO 2 Suspension, add 15g polyethylimide, mix and stir for 30min; add 15g tungstic acid and 0.75g lithium carbonate, mix and stir for 30min, make the precursor of tungsten bronze adhere to VO 2 Add 5g of urea to the surface of the particles, and react at a constant temperature of 25°C for 4h to obtain a suspension. After centrifugal precipitation, vacuum drying at 100°C to obtain VO coated with tungsten bronze precursor 2 powder; put the obtained powder into a heating furnace, heat treatment at 100°C for 8 hours, and obtain VO 2 @Li 0.3 WO 3 Nano-composite powder with core-shell structure, in which the core layer VO 2 M / R phase, shell Li 0.3 WO 3 The thickness is 15nm. Prepared VO 2 @Li 0.3 WO 3 Core-shell nanocomposite powder can make VO 2 The phase transition reaction time is shortened by 2 minutes. .

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Abstract

The invention discloses a high-efficiency thermochromic nano composite powder with a core-shell structure. The composite powder takes a VO2 layer as a core layer and a tungsten bronze compound layer as a shell layer; the VO2 layer is vanadium dioxide nano-powder, the smallest dimension in three-dimensional dimensions of the VO2 layer is not more than 100nm, and the tungsten bronze compound layer is MxWO3, wherein M is selected from any one of NH4+, Cs+, K+, Na+ or Li+; the value of x ranges from 0.01 to 0.8; and the thickness of the tungsten bronze compound layer is less than 60nm, an infraredabsorption characteristic of a tungsten bronze material is utilized to enable the shell layer to absorb heat, and the heat is quickly transferred to VO2 particles in the core layer through the closely connected core-shell structure, which results in the temperature rise and phase change of VO2, so as to reduce the ambient temperature required by the phase change of VO2, improve the thermal response speed of VO2, shorten the phase change reaction time and achieve an effect of efficient thermochromism.

Description

Technical field: [0001] The invention relates to the field of new energy-saving and environment-friendly materials, in particular to a high-efficiency thermochromic nano-composite powder with a core-shell structure and a preparation method thereof. Background technique: [0002] With the depletion of global non-renewable energy and the increasing pollution of traditional petrochemical energy, the development and utilization of new energy has become a research hotspot and development trend in countries around the world. Solar energy is not only rich in resources and inexhaustible, but also has no pollution to the environment. It is a perfect clean energy. The most common use of solar energy is lighting, but when we use sunlight (visible light band) for lighting, we also pass the heat of sunlight (near-infrared band). When the temperature is high in summer, we hope to block the heat in the infrared region from entering the room to reduce the air conditioning load. When the te...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K9/00C09K11/02B82Y20/00B82Y30/00B82Y40/00C03C17/00
CPCB82Y20/00B82Y30/00B82Y40/00C03C17/006C09K9/00C09K11/02
Inventor 肖秀娣徐刚程浩亮郇昌梦陆源詹勇军蒲泽伟万溧
Owner GUANGZHOU INST OF ENERGY CONVERSION - CHINESE ACAD OF SCI
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