Electromagnetic self-encapsulation strategy to develop Al-matrix composite phase change material for thermal energy storage

Abstract How to break through the corrosion rupture limit of eutectic Al-Si phase change material (PCM) in iron-based encapsulation container has been a major challenge for realizing the high temperature waste heat recovery in metallurgical industry. Herein, we proposed a self-encapsulation strategy of eutectic Al-Si PCM with no need of container via constructing the 3D-honeycomb-SiC reinforced Al matrix composite with Si-rich◎Si-poor cladding structure ([SiC&Si-rich]◎EAl-Si), which can fundamentally address the corrosion issue. Strikingly, such a structure feature delivers the excellent structural stability and superior energy storage capacity with a high thermal conductivity of 96 ~ 62 W·m−1·°C−1 at 75 ~ 550 °C (increased by ~ 10% after 1000 cycles), and giant discharge energy density of 490 J·g−1 (with the capacity retention of over 98.9% after 1000 cycles). Compared with the Al-Si@Al2O3 microcapsule with core–shell architecture, the discharge energy density of the [SiC&Si-rich]◎EAl-Si was enhanced by 19.3%~105.7%. In comparison with conventional iron-based container encapsulation, the [SiC&Si-rich]◎EAl-Si demonstrates a 10.7% and 16.2% improvement in efficiency of charge and discharge process. More importantly, this self-encapsulation strategy of eutectic Al-Si PCM can be further constructed continuously by the electromagnetic continuous separation technology, which can potentially pave the way to achieve the large scale production of the [SiC&Si-rich]◎EAl-Si, thus providing technological support for accelerating the application process of eutectic Al-Si PCM in metallurgical industry.