Thermal performance enhancement of high durability alloy microencapsulated phase change material (MEPCM)/ceramic composites based on industrial graphene

Metallic phase change material (PCM)/ceramic composites have emerged as promising candidates for medium and high-temperature thermal energy storage (TES) due to their excellent performance. However, challenges associated with leakage and oxidation in metals, along with the limited thermal conductivity of ceramic matrices, restrict further performance enhancement. Herein, an alloy microencapsulated phase change material (MEPCM) is prepared as a PCM using the “double-layer coating, sacrificial inner layer” method, followed by compounding it with a ceramic matrix and industrial graphene (IG). Based on this, a novel IG/SnBi58 MEPCM/ceramic composite is prepared and its performances are investigated. The results show that the composite with 12 wt% IG exhibits optimum performance: a thermal conductivity of 5.75 W/(m·K), 86.1% higher than without IG, melting enthalpy of 73.71 J/cm3, and compressive strength of 49.38 MPa. Furthermore, the microencapsulation of alloys fundamentally solves the PCM leakage issue within the composite and enables its good component compatibility. The heat storage density reaches 399.1 MJ/m3, over 2.3 times that of traditional quartz sensible heat storage materials. Owing to the thermally expanded cavities created by “double-layer coating, sacrificial inner layer” method, the prepared MEPCM demonstrates high thermal reliability, so the composite maintains stable thermal properties and chemical structure after 500 thermal cycles. Finally, the comparative analysis reveals that the composite combines higher thermal conductivity, compressive strength, heat storage density, and thermal cycle stability than other composite heat storage materials. This work provides a new strategy to meet the demand for high-performance heat storage materials in medium-temperature TES applications.