Title
The impact of bead milling on the thermodynamics and kinetics of the structural phase transition of VO2 particulate materials and their potential for use in thermochromic glazing
Author
Calvi, L.
van Geijn, R.
Leufkens, L.
Habets, R.
Gurunatha, K.L.
Stout, K.
Mann, D.
Papakonstantinou, I.
Parkin, I.P.
Elen, K.
Hardy, A.
van Bael, M.K.
Buskens, P.
Publication year
2022
Abstract
The thermodynamics and kinetics of the structural phase transition from monoclinic VO2 (M) to rutile VO2 (R) and vice versa were studied for particulate materials obtained by bead milling of VO2 (M) powder. Using wet bead milling, we decreased the particle size of VO2 (M) powder from ∼1 μm to 129 nm. With progressive milling, the switching enthalpy decreased from 47 J g−1 to 29 J g−1 due to a loss of crystallinity. The switching kinetics were studied using Friedman's differential isoconversional method. The activation energy |Eα| decreases with increasing difference between the actual temperature of the material and its switching temperature (T0). Furthermore, |Eα| decreases with progressive milling, and kinetic asymmetry is induced. For milled particulate materials, |Eα| is lower for the switch from VO2 (R) to VO2 (M) than for the opposite switch. For hydrothermally synthesized nanoparticles, |Eα| is in the same order of magnitude, albeit with inverse switching asymmetry. Latter may result from different defects that are introduced during both preparation techniques. Applying layers of milled particulate material to glass sheets yielded thermochromic coatings with luminous transmission of 40.7% and solar modulation of 8.3%. This demonstrates that milled VO2 particles have potential for use in energy efficient thermochromic windows.
Subject
Activation energy
Bead milling
Coating
Isoconversional kinetic analysis
Structural phase transition
Thermochromic
Vanadium dioxide
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http://resolver.tudelft.nl/uuid:e953c0a4-de11-45e8-8c73-e1a7ae84dda1
DOI
https://doi.org/10.1016/j.solmat.2022.111783
TNO identifier
970650
Publisher
Elsevier B.V.
ISSN
0927-0248
Source
Solar Energy Materials and Solar Cells, 242 (242)
Document type
article