Shape-Stabilized Cellulose Nanocrystal-Based Phase-Change Materials for Energy Storage

Shape-stable solid–solid phase-change material (PCM) has attracted much attention due to its excellent thermal properties and shape stability. In this study, cellulose nanocrystal (CNC) was introduced as a high thermal-conductivity nanoskeleton material, and polyethylene glycol (PEG) was used as a solid–liquid phase-change functional material. A green, simple aqueous phase radical polymerization method was used to synthesize shape-stable CNC-based solid–solid phase-change material. The effect of different reaction times on the chemical structure, crystallization ability, thermal stability, and phase transformation properties of the PCM was investigated. All PCM samples showed excellent thermal stability when the temperature was lower than 300 °C. In particular, the synthesized PCM at 12 h had a melt phase transition temperature of 47.1 °C and a phase transition enthalpy up to 82.3 J/g. In addition, the phase-change enthalpy and temperature of PCM-12h did not change significantly after 120 heating and cooling scans. The PCM-12h showed thermal reliability, shape stability, controlled phase-change behaviors, and good heat storage/release properties after thermal treatment. The PCM has potential applications in smart heat storage and temperature control textiles/clothes, building insulation materials, and other energy storage fields.