Bird skeleton-inspired 3D hollow diamond-enhanced PEG composite PCM for photothermal conversion and thermal management

Abstract

The use of porous skeletons for encapsulating phase change materials (PCMs) is an effective approach to addressing issues such as leakage, low thermal conductivity, and poor photothermal conversion efficiency. Inspired by the hollow skeletal structure found in birds in nature, high-quality 3D interconnected hollow diamond foam (HDF) was fabricated using a series of processes, including microwave plasma chemical vapor deposition (CVD), laser perforation, and acid immersion. This HDF was then used as a scaffold to encapsulate PEG2000. The results demonstrate that HDF significantly reduces the supercooling degree and latent heat discrepancy of PEG2000. Compared to pure PEG2000, the thermal conductivity of the HDF/PEG increased by 378%, while its latent heat reached 111.48 J/g, accompanied by a photothermal conversion efficiency of up to 86.68%. The significant performance improvement is mainly attributed to the combination of the excellent properties of the diamond with the inherent advantages of the 3D interconnected structure in HDF, which creates a high-conductivity transport network inside. Moreover, the HDF/PEG composite extends the temperature cycling time of electronic components by 4 times for heating and 2.3 times for cooling, thereby prolonging the operational lifetime of electronic devices. HDF/PEG offers an integrated solution for solar energy collection, photothermal conversion, heat dissipation in electronic components, and thermal energy transfer/storage. This innovative approach provides innovative ideas for the design and fabrication of composite PCMs and has great application potential, such as solar energy utilization, thermal management, and thermal energy storage.