Directional fiber framework wrapped by graphene flakes for supporting phase change material with fast thermal energy storage properties. (January 2023)

• Record Type: Journal Article
• Authors: Zhao, Chengzhi; He, Xingwei; Sheng, Nan; Zhu, Chunyu
• Is Part Of: Journal of energy storage. Volume 57(2023)
• Publication Date: 2023-01
• Subjects: Phase change materials -- Biomass carbon -- Thermal energy storage -- Heat transfer enhancement -- Solar energy; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2022.106304
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: Organic phase change materials (PCMs) have low thermal conductivity and poor form stability, which prohibit their usage in high-efficient heat storage and thermal management. This study demonstrated how to efficiently fabricate phase change composites (PCCs) with directional thermal conductivity and good form stability using vertically aligned carbon fibers as supporting scaffolds. Cotton blankets with aligned fibers were firstly impregnated with graphene flake solutions, which were then rolled to columns along the fiber direction and subsequently carbonized to obtain the porous carbon fiber scaffolds. PCCs were prepared by vacuum impregnation of paraffin into the scaffolds. The porous scaffolds supported PCCs showed good shape stability and greatly improved thermal transfer properties, which were especially endowed with a directional heat conductivity as a result of the vertically arranged hollow carbon fiber structure. The thermal conductivity of PCCs along the axial direction of the fibers was greater than along the lateral direction, because the arranged fibers provided the majority of the thermal transfer path in PCCs. With a carbon content of 19.46 wt%, the axial thermal conductivity was 2.13 W K −1 m −1, which was twice of the lateral one and 8.5 times of the PW. Last but not least, the PCCs also possessed high latent heat capacity, high thermal cycling and chemical stability. These results suggest that the novel carbon scaffolds may enable PCCs with directionally improved thermal transfer properties. Highlights: Biomass cotton cloth-derived porous carbon scrolls are prepared for supporting PCMs. Porous carbon scrolls consisting of oriented carbon fibers with graphite flakes coated on the outside of the fibers. The axial and lateral thermal conductivities of the sample are 2.13 and 1.06 W K −1 m −1 . The composite PCM indicates good anti-leakage property. The phase change enthalpy of the composite is 148.8 J g −1 .