The development of high-performance
shape-stable phase change material
composites (SPCMs) with high phase change enthalpy and high conversion
efficiency, especially with good photochromic properties, is essential
for thermal energy storage. Here, we report that one type of SPCMs
with both photochromic and phase change energy storage is obtained
by incorporating organic binary composite PCMs (hexadecanol/coconut
oil, H/C) and photochromic phosphotungstic acid (PA) into Ochroma
pyramidale wood-based cellulose microframe (DOW) through simple vacuum
impregnation. When the ratio of hexadecanol to coconut oil is 3:7
and the ratio of phosphotungstic acid to N,N-dimethylacetamide is 4:13.6, the SPCM composite material
(DOW-H3C7-4PA) represents a high phase transition enthalpy of 163.7
J/g and an appropriate phase transition temperature of 42.55 °C
that can be applied to the environmental temperature adjustment of
high-temperature areas (>40 °C) mentioned in this paper, in
addition
to the excellent thermal stability and photochromic stability; for
example, even after 100 thermal cycles and UV radiation cycles, its
phase transition enthalpy remains almost unchanged. The DOW-H3C7-4PA
composite material also shows good shape stability and leakage resistance.
In addition, the high photothermal conversion efficiency (65.71%)
of DOW-H3C7-4PA is considered to be a promising candidate for photothermal
energy storage applications. Therefore, the manufactured SPCMs (DOW-H3C7-4PA)
have high latent heat, good melting/freezing cycle reliability, high
photochromic stability, and remarkable light-to-heat energy conversion
ability, making them show broad application prospects in energy conversion
and storage devices.