TY - JOUR
T1 - Development of a microencapsulated Al-Si phase change material with high-temperature thermal stability and durability over 3000 cycles
AU - Sheng, Nan
AU - Zhu, Chunyu
AU - Saito, Genki
AU - Hiraki, Takehito
AU - Haka, Miki
AU - Hasegawa, Yuta
AU - Sakai, Hiroki
AU - Akiyama, Tomohiro
AU - Nomura, Takahiro
N1 - Funding Information:
The authors greatly appreciate the nancial support from the JSPS KAKENHI Grant Number 15H05567 and Centre for Advanced Research of Energy and Materials, Hokkaido University. A part of this work was conducted at Hokkaido University, supported by the “Nanotechnology Platform” Program of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
Publisher Copyright:
© 2018 The Royal Society of Chemistry.
PY - 2018
Y1 - 2018
N2 - Development of highly durable phase change materials (PCMs) above 500 °C is essential in future high-temperature thermal energy storage systems. In this study, we report the fabrication of microencapsulated PCM (MEPCM) microspheres with high-temperature stability and cycling durability over 3000 cycles. The MEPCM consists of an Al-Si alloy core (Al-25 wt% Si; melting point of 577 °C) and a self-repairing Al2O3 shell. The uniform and highly durable Al2O3 shell is processed in three indispensable steps. Firstly, a boehmite treatment in an Al(OH)3 turbid solution under an optimal pH value of 8 is used for the formation of AlOOH and Al(OH)3 shell precursors. Secondly, additional Al(OH)3 is further precipitated on the surface to enhance the formation of a thicker shell. Finally, a stable and self-repairing two-phase (α-Al2O3 and -Al2O3) Al2O3 shell is formed by heat-oxidation in an O2 atmosphere. The surface morphology, crystal structure of the shell, thermal durability, cycling stability and the shell formation mechanism are carefully investigated. The newly introduced boehmite and precipitation pre-treatments under optimal conditions can reinforce the formation of a thick and highly compact shell with small α-Al2O3 and -Al2O3 grains, which are beneficial to disperse the thermal stress during high-temperature cycling and restrain crack propagation. The excellent achievement of durability over 3000 cycles can promote the practical applications of the MEPCM for high-temperature thermal storage, for example, it can be applied to the thermal storage system of a concentrated solar power plant for more than 6 years based on the reported durability.
AB - Development of highly durable phase change materials (PCMs) above 500 °C is essential in future high-temperature thermal energy storage systems. In this study, we report the fabrication of microencapsulated PCM (MEPCM) microspheres with high-temperature stability and cycling durability over 3000 cycles. The MEPCM consists of an Al-Si alloy core (Al-25 wt% Si; melting point of 577 °C) and a self-repairing Al2O3 shell. The uniform and highly durable Al2O3 shell is processed in three indispensable steps. Firstly, a boehmite treatment in an Al(OH)3 turbid solution under an optimal pH value of 8 is used for the formation of AlOOH and Al(OH)3 shell precursors. Secondly, additional Al(OH)3 is further precipitated on the surface to enhance the formation of a thicker shell. Finally, a stable and self-repairing two-phase (α-Al2O3 and -Al2O3) Al2O3 shell is formed by heat-oxidation in an O2 atmosphere. The surface morphology, crystal structure of the shell, thermal durability, cycling stability and the shell formation mechanism are carefully investigated. The newly introduced boehmite and precipitation pre-treatments under optimal conditions can reinforce the formation of a thick and highly compact shell with small α-Al2O3 and -Al2O3 grains, which are beneficial to disperse the thermal stress during high-temperature cycling and restrain crack propagation. The excellent achievement of durability over 3000 cycles can promote the practical applications of the MEPCM for high-temperature thermal storage, for example, it can be applied to the thermal storage system of a concentrated solar power plant for more than 6 years based on the reported durability.
UR - http://www.scopus.com/inward/record.url?scp=85053888337&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85053888337&partnerID=8YFLogxK
U2 - 10.1039/c8ta04708a
DO - 10.1039/c8ta04708a
M3 - Article
AN - SCOPUS:85053888337
SN - 2050-7488
VL - 6
SP - 18143
EP - 18153
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
IS - 37
ER -
