Erythritol confined in multiwalled carbon nanotubes reinforced silica aerogel as novel form-stable phase change materials

In this work, pristine multiwalled carbon nanotubes (MCNTs) and mixed acids treated MCNTs (ACNTs) were applied as reinforcement fillers to prepare silica aerogels via ambient pressure drying followed by lyophilization. The prepared aerogels were then used as supporting materials to adsorb meso-erythritol (ME) to obtain novel form-stable PCMs by vacuum infiltration. Investigation of the prepared form-stable PCMs revealed that the ACNT/SiO2 aerogels possessed higher porosity than MCNT/SiO2 aerogels due to that the ACNTs exhibited stronger interactions with silica than the MCNTs, and could more effectively prevent the prepared ACNT/SiO2 aerogels from collapsing and shrinking during drying. Consequently, the loading of ME in the form-stable PCMs supported by ACNT/SiO2 aerogels (AFPCMs) was greatly higher than that in the form-stable PCMs supported by MCNT/SiO2 aerogels (MFPCMs). When ACNT/SiO2-6 aerogel, in which 60 mg ACNTs were used as reinforcement filler, was applied as supporting material, the obtained form-stable PCM (AFPCM-6) exhibited a very high melting latent heat of 297.3 J/g, an elevated crystallizing temperature of 56 °C and an improved crystallizing latent heat of 231 J/g. Besides, the latent heat storage/release properties of AFPCM-6 maintained stable enough over 50 melting/crystallizing cycles. Meanwhile, the thermal conductivity of AFPCM-6 was 37.5 % higher than that of pure ME. Hence, AFPCM-6 could be an excellent form-stable PCM and could find its applications in related fields.