Study on the supercooling degree and nucleation behavior of water-based graphene oxide nanofluids PCM

• Graphene oxide nanosheets used as additive of water PCM.
• The supercooling degree of graphene oxide nanofluids can be reduced by 69.1%.
• The nucleation was started in advanced, shorting the time by 90.7%.
• Ice nucleus can only grow on the top or bottom surface of the nanosheet.

This article aimed to study the supercooling degree and nucleation behavior of nanofluids phase change material. The nanofluids were prepared by adding small fraction of graphene oxide nanosheets in deionized water without any dispersants. The supercooling degree of nanofluids with different concentrations was tested experimentally. The results show that the supercooling degree can be reduced by 69.1%, and the nucleation was started in advance, shorting the time by 90.7%. Theoretical analysis based on the heterogeneous nucleation theory indicates that ice crystal nucleus cannot grow on the thickness surface of the graphene oxide nanosheet, while it can grow on the top or bottom surface of the nanosheet only when the supercooling degree ΔT and the nanosheets size D meet the formulaD⋅ΔT≥4.2×10−8. Our study implies that graphene oxide nanofluids have the potential to be used as PCMs in cold storage applications because of their low supercooling degree and rapid nucleation behavior.