3D structure fungi-derived carbon stabilized stearic acid as a composite phase change material for thermal energy storage

Abstract

Stearic acid (SA)/fungi-derived carbon (FDC) composite phase change materials (PCM) were fabricated by vacuum impregnation, where three types of FDC (FDC-C, FDC-H, and FDC-K) as carrier were synthesized by diverse synthetic procedures of carbonization. The FDC-K modified by synergistic hydrothermal and KOH-assisted calcination process had a 3D-cellular structure with considerably higher inner surface area (1799.48 m2 g−1) and cumulative pore volume (0.7476 cm3 g−1) than other matrixes, leading to that a loading capability value of SA (LC, %) in SA/FDC-K composite was up to 344.64%. X-ray diffraction and Fourier transform infrared spectroscopy shown that physical interaction instead of chemical reaction happened between FDC and SA. X-ray photoelectron spectroscopy indicated that KOH-assisted calcination treatment improved oxygenic functional groups on matrix surface so that facilitating SA loading. Raman spectra illustrated the IG/ID value of three amorphous carbons were ∼1.04. For SA/FDC-K composite, it had a melting and freezing enthalpy of 144.8 J g−1 and 142.6 J g−1, respectively, and phase transition point of 52.72 °C and 52.95 °C, respectively. The thermal conductivity (0.574 W m−1 K−1) was 115% higher than pure SA. It was also stable in terms of thermal and chemical after thermal cycles in heating and cooling. Thus, the SA/FDC-K exhibited high phase transition enthalpy and excellent thermal stability has potential application in thermal energy storage.