One-step in-situ green synthesis of cellulose nanocrystal aerogel based shape stable phase change material

The confinement of phase change material (PCM) within 3D porous structure has been identified as an attractive and efficient strategy to fabricate high performance shape stable PCM (SSPCM). Nevertheless, the conventional fabrication techniques suffer limitations such as cumbersome preparation process, the usage of toxic reagents and high-cost additives. Herein, an ingenious and green one-step in-situ synthesis method was developed to prepare SSPCM, which was constructed by the combination of polyethylene glycol (PEG) within chemically cross-linked cellulose nanocrystal (CNC) aerogel. The as-prepared CNC/PEG phase change aerogel composite exhibited excellent shape stability, even when compressed upon the melting point of PEG, the composite still maintained its original shape without any leakage. Meanwhile, the composite possessed high phase change enthalpy of 145.8 J/g and extraordinary cyclic reversibility after 100 thermal cycles. Specifically, the thermal conductivity and mechanical properties of the novel CNC/PEG phase change aerogel composite were dramatically improved due to the higher thermal conductivity of CNCs and the chemically cross-linked CNC framework. This work established a promising sustainable approach for the exploitation of CNC/PEG phase change aerogel composite with outstanding comprehensive properties, which would offer great opportunities for applications in thermal energy storage systems.