Recent developments in thermo-physical property enhancement and applications of solid solid phase change materials

Intrinsic photothermal phase change materials with enhanced toughness and flexibility for thermal management in extreme environments

Thermosetting solid–solid phase change materials composed of poly(ethylene glycol)-based two components: Flexible application for thermal energy storage

Numerical Model for Solidification and Melting of PCM Encapsulated in Spherical Shells

Solidification enhancement of PCM in a triplex-tube thermal energy storage system with nanoparticles and fins

Phase change materials (PCMs) are extensively explored for thermal energy storage (TES) applications. While paraffin wax is the most widely studied organic PCM, non‐paraffinic bio‐based fatty acids offer a more sustainable alternative. This study systematically evaluates seven palm fatty acids: caprylic, capric, lauric, myristic, palmitic, stearic, and oleic acids, focusing on thermal stability, reliability, and metal compatibility, compared with paraffin wax. In addition to standard thermal characterization, a heat absorption‐release test was performed to assess heat storage performance. PCM properties were analyzed before and after two thermal reliability assessments: thermal treatment (up to 700 h) and thermal cycling (up to 350 cycles). Differential scanning calorimetry (DSC) determined phase change temperature, latent heat, and specific heat capacity ( C p ), while thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) assessed thermal and chemical stability. The palm fatty acids exhibited slight variations in phase change temperature (0.03°C–3.6°C) and moderate melting latent heat reductions (−3.2% to −6.2% after thermal treatment, −7.5% to −13.8% after thermal cycling), comparable to paraffin wax (0.04°C–1.32°C, −7.0%, −10.3%, respectively). Similar to paraffin wax, changes in C p , heat storage performance, TGA, and FTIR results further confirmed the thermal reliability of palm fatty acids. Twelve‐week corrosion tests showed decreasing corrosion rates with time and confirmed the compatibility of all tested PCMs with stainless steel, aluminum, copper, and brass, with most corrosion rates remaining below the critical threshold for long‐term use. Overall, palm fatty acids demonstrate high thermal reliability, stability, and metal compatibility comparable to paraffin wax, establishing them as sustainable bio‐based PCMs for long‐term TES applications.

1,3-Bisstearoylurea and 1,1,3,3-tetrastearoylurea were produced as solid-solid phase change materials (SS-PCMs) for potential solar thermal energy storage (TES) applications via condensation of urea with the respective amount of carboxyl chloride (stearoyl chloride). Both 1,3-bisstearoylurea and 1,1,3,3-tetrastearoylurea were characterized by Fourier-transform infrared (FT-IR), 1H nuclear magnetic resonance, differential scanning calorimetry (DSC), and thermogravimetric (TG) analysis techniques. 1,3-Bisstearoylurea and 1,1,3,3-tetrastearoylurea had considerable melting/crystallization enthalpy. The reason for crystallization was structural symmetry and flexibility of long alkyl groups there. Di and tetra alkyl groups made it possible to discuss the structure-property relationship for organic PCMs. Besides, the compounds were characterized through DSC and FT-IR spectroscopy before and after thermal cycling to determine their thermal reliability. Solid-solid phase change enthalpies of them for melting and crystallization were found 95.86 and −87.6 Jg−1 for 1,3-bisstearoylurea, respectively and 27.7 and −25.8 Jg−1 for 1,1,3.3-tetrastearoylurea, respectively. Thermal conductivity was studied to increase by simply expanded graphite addition. The thermal endurance limits of 1,3-bisstearoylurea and 1,1,3,3-tetrastearoylurea compounds were studied using TG analysis.

The permanently chemically cross‐linking solid–solid phase change materials (SSPCMs) were designed to solve the problem of leakage and poor shape stability during the whole process of phase transformation. However, these materials lead to environment pollution and resources waste because of the non‐recyclability. Therefore, a SSPCMs was fabricated using dynamic thermal reversible Diels–Alder bonds. The prepared SSPCMs exhibited excellent shape, heat storage stability, and reliability and reprocessed ability, resulting from dynamic Diels–Alder bonds. Moreover, the Halloysite nanotubes decorated with Fe3O4 nanoparticles (HNTs@Fe3O4) were used to enhance the thermal conductivity of SSPCMs. When the filler content was 0.5 wt%, the best integrated properties (phase change properties and thermal conductivity) of the SSPCMs were obtained, it had the highest melting and freezing phase change enthalpies about 116.8 and 127.2 J/g, and thermal conductivity value, 0.223 W/m K, which was 101% higher than pure SSPCMs. Hence, the prepared SSPCMs can be considered as promising save‐energy, friendly‐environment thermal management materials.

Solid-solid phase change materials (SSPCMs) are potential materials for energy storage and thermal management, and improving mechanical property and heat transfer performance is the key to practical application. After modified graphene oxide (TGO) was prepared by toluene diisocyanate, a kind of super-tough, form-stable and leak-proof polyurethane composite phase change material (PU-TGO) was constructed by the two-step polymerization of isophorone diisocyanate and 1, 4-butanediol using polyethylene glycol and TGO. TGO has more uniform and stable dispersion than traditional graphene oxide, and its chemical crosslinking with polyurethane phase change materials makes the composite have better shape stability, mechanical strength, thermal conductivity and flexibility. PU-TGO has thermal conductivity and elongation at break up to 0.3072 W/(m•K) and 540%, respectively, and maintains excellent thermal stability and 72.09 J/g enthalpy after 500 thermal cycles. PU-TGO prepared by chemical crosslinks in this paper further demonstrates the great potential of phase change materials in the field of thermal management of new electronic devices.

Titanium dioxide/graphene oxide synergetic reinforced composite phase change materials with excellent thermal energy storage and photo-thermal performances

Salt hydrates are one of the most common inorganic compounds that are used as phase change material (PCM). These are available for a wide range of phase transition temperature for thermal energy storage (TES) application. They have some most desired properties for TES applications like high latent heat value, good thermal conductivity, nonexpensive, and were nonflammable. Besides these, due to the undesirable properties like phase segregation, supercooling, and corrosion to the containers, this PCM not recommended for TES application. To mitigate these issues and to make salt hydrates suitable in TES application, much research has been carried out in past years. This main highlight of this article is to provide a comprehensive overview of the use of salt hydrates, their applications and summarize the research outcomes reported by various researchers to every issue for its TES application. This summarized information will be useful to those who are interested to work on this research area. Along with this literature focuses on the advantages, disadvantages, and mechanism of salt hydrates for TES system during its thermal cycle process.

Thermal optimization of a novel thermo-optically responsive SS-PCM coatings for building enclosures

Emergence of rectangular shell shape in thermal energy storage applications: Fitting melted phase changing material in a fixed space

Solvent-free preparation and performance of novel xylitol based solid-solid phase change materials for thermal energy storage

The phase change material is currently being regarded as an effective cooling media to be applied in the thermal management of lithium batteries-powered vehicles, in which the inorganic hydrate phase change material is desirable and widely investigated due to the high thermal conductivity, latent heat value, and low cost. However, when applied to thermal energy storage applications, supercooling and phase separation are problematic. To effectively circumvent this issue, this work considers utilizing the disodium hydrogen phosphate dodecahydrate as the matrix of the composite phase change material, as the phase transition temperature is suitable for the battery's operating temperature range. Meanwhile, the nucleating agent sodium metasilicate nonahydrate with similar lattice parameters and the thickener carboxymethyl cellulose are used to suppress the supercooling and eliminate the phase separation, respectively. Effects of nucleating agent, surface modified aluminum nitride, and short-cut carbon fiber on the supercooling degree, and thermal conductivity and curing performance in the phase change material are evaluated and discussed in detail to determine the optimal preparation scheme for Na2HPO4·12H2O/modified AlN/CF inorganic composite phase change materials. Experimental results show that the addition of 4 wt% Na2SiO3·9H2O, 4 wt% CMC, 12 wt% modified AlN, and 6 wt% CF reduces the supercooling degree of the composite phase change material to 1.9°C and increases the thermal conductivity to 1.86 W/(m·K). The composite phase change material is found to have a suitable phase change temperature (35°C), high latent heat (249 J/g), excellent shaping effect, and electrical safety performance. In addition, the composite phase change material battery module can effectively control the battery's temperature, with the maximum temperature reduced by 40.9°C at 3C discharge rate and 30°C ambient temperature compared with the natural cooling battery module. The maximum temperature difference of the composite phase change material battery module is shown to be reduced to the minimum value of 0.9°C. Highlights A novel disodium hydrogen phosphate dodecahydrate—modified aluminum nitride—carbon fiber composite phase change material is designed and prepared for battery thermal management systems. The antiwater modification scheme of AlN is proposed and assessed. The effects of AlN before and after modification on the thermal properties of CPCM are compared. The joint use of nucleating agent sodium metasilicate nonahydrate and thermal conductive filler AlN contributes to significantly inhibiting the supercooling of hydrate salt. The addition of CF can effectively increase the thermal conductivity of CPCM and prevent its leakage. CPCM has suitable phase change temperature, high thermal conductivity and latent heat value, excellent electrical safety, and stable curing performance. The battery test bench is constructed and the discharge test of the CPCM battery module is carried out. The results show that the CPCM battery module has excellent cooling performance and temperature uniformity.

Thermo-physical stability of fatty acid eutectic mixtures subjected to accelerated aging for thermal energy storage (TES) application