Inorganic Phase Change Materials Research Articles

Energy Storage in Lightweight Aggregate and Pervious Concrete Infused with Phase Change Materials

This study explores the feasibility of utilizing pervious concrete (PC) incorporating diverse lightweight aggregates (LWAs) integrated with phase change materials (PCM) for applications where forced air cooling would be advantageous. The use of such a component provides latent and sensible heat that can cool forced air applications, offsetting ambient temperature increases that occur during the day. Macro- and microencapsulation techniques were used to incorporate inorganic PCM in the PC. The macro-encapsulation technique involved enclosure of PCM within a stable shell prior to addition into the concrete. The microencapsulation technique involved the impregnation of PCM into porous lightweight aggregate. To overcome the PCM reaction with the concrete constituents, an epoxy coating was utilized. The design of the PCM concrete mix and comprehensive laboratory assessment of porosity, water permeability, PCM absorption capacity, compressive strength, and microstructure of the LWAs are detailed. The test results indicate that LWAs have high PCM impregnation rates ranging from 32 % to 57 % by volume. The compressive strengths of PC using LWAs were reduced by 25 % to 65 % when using microencapsulation. The use of microencapsulation was found to reduce the pressure drop under air flow due to the increase in aggregate size as a result of the coating thickness. PCM-PC with a shell thickness of 100 mm, resulted in a pressure drop of less than 100 Pa at a velocity of 0.35 m/s. The use of macro-encapsulated PCM in PC was sensitive to the phase of the PCM, where the liquid phase reduced the compressive strength by 67 %. The failure occurred within the macro-encapsulated PCM at the liquid phase temperatures and at the interface between the encapsulated PCM at solid phase temperatures. The heat transfer provided by the LWA infused PCM when used in a packed aggregate bed or in PC, was shown to match expected latent and sensible heat estimates based on the thermal properties of the materials. This systematic investigation provides valuable insights into LWAs and PCM performance in pervious concrete, offering a comprehensive understanding of their interaction in cooling applications.

Thermo-energy performance of a phase change material integrated into lightweight hollow concrete roofs in warm–subhumid climate

The use of phase change materials in building envelopes has attracted the attention of researchers to minimize cooling and heating loads and for thermal comfort regulation. A research gap was found regarding the numerical analysis of lightweight roofs with PCM considering conjugate heat transfer. Thus, this paper aims to evaluate the thermal performance of a lightweight hollow concrete roof with a phase change material (PCM) in a subhumid climate. Three roof configurations with two PCMs were numerically analyzed through computational fluid dynamics. Simulations were conducted using the open-source code OpenFoam and were verified and validated with good agreements proving the confidence of the proposed methodology for building envelope design purposes. The roof configurations with fully-filled PCM exhibited the best thermal behavior, reaching higher temperature reductions between 1.4 °C to 2.0 °C, respectively, and reductions of indoor peak heat flux by approximately 47 % compared with the reference case. The roof fully-filled with an inorganic PCM with a melting temperature of 25 °C was the most energy-efficient roof configuration because it achieved the highest energy savings of 65.5 %, lowest electricity costs of 0.85–4.33 USD m−2, and lowest CO2 emissions of approximately 18.31 kgCO2e m−2. The results demonstrated that the utilization of PCM into lightweight concrete roofs in subhumid climates is very promising.

Development of a novel composite phase change material based on paints and brick for energy storage applications in agricultural greenhouses

This study addresses challenges associated with supercooling, phase separation, and inadequate thermal properties in Na2SO4·10H2O (SSD) by expanding the application of inorganic hydrate salt phase change materials within agricultural greenhouses. A novel composite phase change material, Na2SO4·10H2O-Al2O3 (NAPCM), was successfully synthesized using the vacuum impregnation method. NAPCM was strategically incorporated into paints and hollow bricks, leading to the creation of innovative phase change paint and phase change bricks designed for efficient thermal energy storage in agricultural greenhouses. The investigation revealed the homogeneous dispersion of porous Al2O3 particles in SSD, effectively preventing phase separation in NAPCM and ensuring its durable shape stability. The interaction between SSD and porous Al2O3 remained purely physical, with porous Al2O3 acting as an effective modifier to adjust various thermal properties of SSD. Optimal mass ratio determination for the combination of paint and NAPCM particles resulted in a 9:1 ratio, ensuring the uniform distribution of NAPCM particles within the paint matrix. This achieved a particle size averaging 290.93 μm with no discernible leakage features. The phase change paint exhibited an impressive solid content of 56.62 %, demonstrating exceptional resistance to water, alkali, salt, and abrasion. In thermal plate testing, the phase change paint significantly decelerated the heating rate. Infrared thermal imaging observations depicted circular areas with temperatures notably lower than their surroundings, indicating NAPCM's ability to impede heat absorption during the heating process, thereby reducing the rate of temperature change. The phase change paint also exhibited a slower cooling rate in the cooling test. Simultaneously, phase change bricks demonstrated superior thermal insulation compared to ordinary bricks. Throughout the heat storage phase, the temperature of the phase change greenhouse wall was lower than that of an ordinary greenhouse, while in the heat release phase, it was higher. The phase change greenhouse, relative to its ordinary counterpart, demonstrated superior insulation effects, creating a warm environment conducive to plant growth. This advancement enhances the energy storage performance of agricultural greenhouses, providing a novel solution for improving energy efficiency and environmental sustainability.

Phase change electrolytes for combined electrochemical and thermal energy storage

Inorganic salt-based phase change materials (PCMs) form the basis of next-generation thermal energy storage technologies that store and release energy at temperatures relevant for regulating energy usage in residential environments. Here, we detail a rational approach for designing a multifunctional electrolyte that stores latent heat using polymer-stabilized sodium sulfate and sodium thiosulfate mixture. This formulated PCM also allows rapid sodium ion transport in both the solid and liquid states. This PCM composite electrolyte was prepared by blending the components at elevated temperatures, forming a viscous liquid that can serve as a gel-electrolyte for Na-ion batteries. The addition of sodium borate as a nucleating agent resulted in a PCM composite electrolyte with fusion enthalpy (120 J/g) and a phase transition centered around 25.0 °C with 11 °C supercooling. This PCM electrolyte showed excellent thermal cycling stability (>10 cycles) that also maintains high ionic conductivity (>10 mS cm−1). We show that the electrolyte enables Na ion cycling of the dual anode/cathode material, Na2VTi(PO4)3. These properties make this composite electrolyte a promising material for multifunctional energy storage devices.

In51Bi32.5Sn16.5@SiO2 microcapsules-based composite phase change materials with high thermal conductivity and heat storage density for electronics thermal management

Combining phase change microcapsules and various matrix materials can construct novel composite phase change materials (CPCMs). These composite materials hold immense potential for electronics thermal management, owing to their adjustable heat storage capacity and stable shape. Most previous studies focus on enhancing the thermal conductivity of CPCMs by adding thermally conductive fillers or modifying the microcapsule shells. Nevertheless, achieving both high thermal conductivity and heat storage density simultaneously remains a challenge. In this paper, low melting point alloy (In51Bi32.5Sn16.5) was introduced as core material of the microcapsule to enhance the thermal conductivity, due to its significantly higher thermal conductivity compared to commonly used organic or inorganic phase change materials (PCMs). In51Bi32.5Sn16.5@SiO2 microcapsule was synthesized through the sol-gel polymerization method. Furtherly, a form-stable CPCMs consisting of the microcapsules and silicone rubber (SR) matrix were prepared for electronics thermal management. The In51Bi32.5Sn16.5@SiO2 microcapsules exhibit an impressive thermal conductivity of 13.49 Wm−1 K−1, acting as a dual-functional filler for thermal storage and thermal conduction enhancement. Hence, the CPCMs possess a significantly enhanced thermal conductivity of 0.45 Wm−1 K−1, representing a remarkable improvement of 350 % compared to that of pure SR. In addition, the phase change heat storage density of the CPCMs was as high as 71.73 J/cm3. Notable, the prepared CPCMs demonstrate exceptional heat dissipation performance, resulting in a remarkable 23 °C reduction in chip temperature when applied for thermal management. This study offers a novel perspective on the preparation of microcapsule-based CPCMs for electronics thermal management.

Experimental investigation on the performance of binary carbon-based nano-enhanced inorganic phase change materials for thermal energy storage applications

Phase change materials (PCMs) are considered potential resources for Thermal energy storage (TES) applications. However, the PCMs are limited because of their lower thermal conductivity, resulting in a significant decrease in heat transport and energy storage capability. The foremost objective of the present research is to formulate a novel salt hydrate PCM filled with binary carbon-based nanoparticles (graphene and multi-walled carbon nanotubes) at various weight concentrations and examine the thermophysical properties. A two-step approach is used to formulate binary nanomaterials dispersed salt hydrate PCM. The formulated binary nanocomposite's thermo-physical properties like morphological behaviour, thermal stability, chemical stability, melting enthalpy, optical performance, rate of heat transfer and thermal reliability were characterized. The binary nanoparticle-enhanced nanocomposites can form a decent thermal network, resulting in a remarkable enhancement in thermal conductivity by 160 % (1.2 W/mK) compared to pure salt hydrate. Moreover, a remarkable improvement in optical absorptance and a reduction in optical transmittance by 82.55 % for 0.7 wt% graphene and 0.07 wt% MWCNT enhanced salt hydrate PCM (SAHGrM-0.07) than pure salt hydrate PCM. In addition, the formulated nanocomposites possess excellent heat storage capability, chemical and thermal stability after 300-thermal cycling. The binary carbon-based nanoparticle-enhanced salt hydrate nanocomposites offered acceptable thermal and chemical stability, thermal reliability, and heat transmission characteristics, by this means reflecting its appropriateness for medium-temperature solar TES applications.

Novel Sodium Chloride/Aluminum Oxide Powder-Composite Structure with High Shape-Retention Performance for the Encapsulation of a High-Temperature Phase-Change Material

Inorganic phase-change materials (PCMs) with high melting points have great potential for thermal energy storage systems. Sodium chloride (NaCl) has a high melting point (801 °C) and high latent-heat-storage density (482 kJ/kg). However, it is difficult to encapsulate NaCl using a sintered ceramic shell because of its good wettability against ceramics and high volume-expansion capacity during melting. In this study, a novel NaCl/Al2O3 powder-composite structure was developed as highly stable PCM core material for highly stable encapsulation. The shape-retention performance and the mechanism of NaCl/Al2O3 powder-composite structure during melting were investigated. We have successfully fabricated a NaCl/Al2O3 powder-composite structure, which has a higher NaCl volume ratio of 80 vol% than conventional techniques. The gel-like network structure of Al2O3 particles in molten NaCl was a key structure to keep the shape of the composite ball and to prevent the evaporation of molten NaCl.

Synthesis and characteristic analysis of an inorganic composite phase change materials for medium-temperature thermal storage

Composite phase change materials (CPCM) synthesized using inorganic salt (Na2HPO4·12H2O), lime fruit peel biochar (activated), and boron nitride have been explored as a solution for the medium-temperature thermal energy storage systems in this work. The activated biochar and BN concentrations were varied, and the effects of the activated biochar and BN on the thermal properties, chemical, and thermal stability of the phase change materials (PCM) were studied. XRD and FTIR studies confirmed the chemical stability of the synthesized CPCM samples. Leak test results revealed that the addition of biochar and BN has improved the shape stability. TGA studies revealed the superior thermal stability of the CPCM samples. Composite PCM with 2 g of activated biochar and 0.5 g of BN has exhibited better thermal properties with a latent heat of 121.33 J/g, encapsulation efficiency of 55.9%, and thermal energy storage capacity of 98.2% compared to the pure PCM.

Thermal performance of phase change materials with anisotropic carbon fiber inserts

In thermal energy storage systems, phase change materials (PCMs) are widely used for thermal energy management. Most PCMs have low thermal conductivities, which limits the heat transfer rate within PCM and thus makes the phase-changing process very slow. However, thermal conductivities of PCMs can be altered by inserting targeted additives. We hypothesize that the size and shape of these additive inserts play a key role in thermal management efficiency. To this end, the impacts of carbon fiber (CF) inserts on the phase change behavior and consequent heat transfer efficiencies of inorganic and organic PCMs were investigated using experiments and simulations. Long, anisotropic CFs with high thermal conductivities formed continuous fast heat flux tunnels inside PCMs to enhance the heat transfer. Such CFs could extend the phase change fronts from the limited container-shaped interface to the larger surface of numerous CF inserts inside the PCM. These special CF inserts work with a new heat transfer mechanism, different from conventional small additives or long isotropic CF inserts. The thermal energy release rate increased by 2.5 times with 1 wt.% anisotropic CF inserts in inorganic PCM. However, CF inserts in liquid organic PCM hindered the natural convection and compromised the improved heat conduction. The lab-scale multiphysics simulations support these experimental observations and indicate that CF inserts have potential to enhance heat transfer in inorganic PCMs, but they are less effective in organic PCMs.

Preparation of inorganic molten salt composite phase change materials and study on their electrothermal conversion properties

The EG conductive pathway enables CPCM to achieve direct electrical heating for energy storage and to regulate the temperature module uniformity through electric field control.

Energizing eutectic salt hydrate phase change material using 2D carbon based graphene nanoparticle

Energy being the strongly depended source for development and industrialization, their storage in any form tends to bridge the gap between demand and supply. Renewable energy technology systems now include energy storage as a crucial component. Thermal energy storage is a technique that stores thermal energy by heating or cooling a storage medium. This allows the energy to be used for heating and cooling purposes later on. The present study develops ternary inorganic salt hydrate eutectic phase change material (EPCM) that is intended for cooling buildings. Melting temperature, melting enthalpy and eutectic composition proportion of inorganic salt hydrate of sodium carbonate decahydrate (SCD), sodium phosphate dibasic dodecahydrate (SPDD), and sodium sulphate decahydrate (SSD) are determined using the eutectic melting point theory. Ternary EPCM is synthesised experimentally in accordance with the percentage of salt hydrates. Graphene nanoplatelets are distributed at different weight concentrations of 0.3%, 0.6%, and 0.9% in order to further improve the thermal performance; at higher concentration above 0.9% the graphene nanoplatelets tends to agglomerate. In order to assess the chemical stability and thermal properties of prepared nanoparticle dispersed PCMs, are experimentally assessed. Findings confirm the ternary EPCM's chemical stability and raise its latent heat with graphene nanoplatelets.

Hybrid Polymer Salogels for Reversible Entrapment of Salt-Hydrate-Based Thermal Energy Storage Materials.

One of the challenges preventing wide use of inorganic salt hydrate phase change materials (PCMs) is their low viscosity above their melting point, leading to leakage, phase segregation, and separation from heat exchanger surfaces in thermal management applications. The development of a broad strategy for using polymers that provide tunable, temperature-reversible shape stabilization of a variety of salt hydrates by using the lowest possible polymer concentrations is hindered by differences in solubility and gelation behavior of polymers with change in the type of ion. This work addressed the challenge of creating robust, temperature-responsive shape-stabilizing polymer gels (i.e., salogels) using a low cost PCM, calcium chloride hexahydrate (CaCl2·6H2O, CCH). Due to the extremely high (9 M) concentration of chloride ions and the tendency to salting-out polymer chains, the previous strategy of using single-polymer salogels was not successful. Thus, this work introduced a strategy of using two polymers, poly(vinyl alcohol) and ultrahigh molecular weight polyacrylamide (PVA and PAAm, respectively), along with borax as a cross-linker to achieve temperature-reversible, shape-stable salogels. This system resulted in robust salogels whose gel-to-sol transition temperature (Tgel) was tunable within an application-relevant range of gelation temperature (30-80 °C). This behavior was enabled by a synergistic combination of dynamic covalent cross-links between PVA units and entanglements of PAAm chains which were combined into a single hybrid network. The hybrid salogels had <5 wt % polymer content, maintaining ∼95% of the heat of fusion of the pure PCM. Importantly, the noncovalent nature of gelation supported thermo-reversibility of gelation, shape stability, and retention of thermal properties over 50 melting/crystallization cycles.

Optical performance and chemical stability evaluation of new era phase change material: Activated by hybrid nanoparticle

Inorganic salt hydrate phase change materials (PCMs) are ahead of organic PCMs in terms of energy storage ability and safety as they are non-flammable. However the major hindrance with inorganic PCM are degree of supercooling and low thermal conductivity though better than organic PCM. The common technique to enhance the thermal conductivity is via dispersion of metal and carbon nanoparticle. Though they enhance the thermal conductivity of the nanocomposite, with continuous operation the nanoparticle agglomerate and settles down owing to their density. Henceforth, in the current research work we conduct an experimental investigation to enhance the optical and thermal performance of commercialised inorganic salt hydrate PCM using metal-carbon hybrid nanoparticle. We disperse graphene silver nanoparticle at different weight ratio adopting a two-step method followed by probe sonication to ensure uniform dispersion. We achieve a highly stable nanocomposite with 584% increase in optical absorbance of electromagnetic waves and 86% decrease in transmittance. Thermal management of electronic gadgets has evolved to be a major consideration of research as overuse of gadgets lead to rapid temperature rise and is in need of passive cooling system. Henceforth the newly developed nanocomposite phase change materials (PCMs) not only acts as thermal batteries but can also be opted as energy materials for thermal regulation and heat mitigation.

Use of 3D printed concrete components for thermal energy storage

Effective thermal energy storage is key to expanding the use of thermal energy, which plays an important role in mitigating the energy crisis worldwide. Digital construction via additive manufacturing technology, has received an increasing interest over the past decades because it facilitates construction of geometrically complex objects at reduced construction time and cost compared to conventional construction techniques. This study combines these concepts and examines the suitability of concrete components 3D printed by selective binder activation and infused with phase change materials (PCM) for thermal energy storage applications. Immersion and vacuum impregnation techniques were used to incorporate organic and inorganic PCMs. The porosity, water and PCM absorption capacity, compressive strength, and microstructure of the 3D printed components were evaluated. The test results indicate that the base 3D printed concrete has a porosity of 41% which facilitates high PCM absorption. The absorption was most effective using vacuum assistance with the inorganic and organic volumetric absorptions reaching 39–45% and 34–40%, respectively. The compressive strength was impacted by the use of inorganic PCM. The microscopy results indicated delayed cement hydrate formation with minimal formation at early ages. The heat transfer provided by the infused PCM was shown to match expected latent and sensible heat transfer based on the thermal properties of the materials.

Advancements in Phase Change Materials: A Path to Sustainable Energy Solutions in China

With the rapid development of China, the country's demand for energy has significantly increased. According to the "World Energy Outlook 2020," China's annual average growth rate of primary energy consumption is 1.9%, and it is predicted that China's energy consumption will account for over 20% of global energy consumption by 2050. In the energy budget, 90% is allocated to thermal energy conversion, transmission, and storage. Facing an impending energy crisis, enhancing energy production while minimizing energy loss has become a matter of widespread concern. Phase Change Materials (PCMs), also called phase change energy storage materials, have garnered attention as a novel energy-efficient and environmentally friendly material. PCMs refer to substances that undergo a change in state and provide latent heat without changing their temperature. Phase change thermal storage materials utilize phase transitions during heat exchange processes to store energy by means of these phase changes. Compared to chemical energy storage materials, PCMs offer high thermal efficiency and energy storage density, maintain constant temperature, and are more easily controllable. They hold great potential as a promising material in the field of thermal energy storage and have been widely applied in areas such as solar energy, lithium batteries, building insulation, and medical applications. This article offers a comprehensive overview of the principles and classification of Phase Change Material (PCM), including organic PCM, inorganic PCM, and composite PCM. It discusses their applications in solar thermal energy storage, cooling of photovoltaic panels, building materials, and industrial waste heat recovery. The article also highlights China's research and development efforts in these areas, emphasizing the country's significant contributions to advancing PCM technology.

Expanded graphite intersperse reliable binary eutectic phase change material for low temperature thermal regulation systems

Inorganic phase change materials (PCMs) frequently stuck by ineffaceable thermal conductivity and degree of supercooling for thermal energy storage (TES) accomplishment. The present research work is dedicated to resolve this problem by developing a unique inorganic salt hydrate based binary eutectic PCM employing sodium sulphate decahydrate (SSD) and sodium phosphate dibasic dodecahydrate (SPDD) in eutectic mixture ratio 62:38 mass percentage. The peculiar eutectic composition of SSD/SPDD developed with melting and bath sonication technique manifests eutectic latent heat of 207.4 J/g and eutectic melting point of 27.8 °C. Furthermore, to elevate thermal performance and to descent degree of supercooling three dimension expanded graphite (EG) is interspersed as nanoparticle. Optical absorbance of composite PCM elevated from 0.16 for SSD/SPDD to 0.92 with SSD/SPDD + EG nanoparticles; inversely transmissibility of the composite reduced by 82.13 %. Heat flow curves ensures the melting temperature (26.9 °C–28.7 °C) of EG dispersed composite to be within the operating condition with latent heat of 220.4 J/g at 2.0 % of EG owing to the intermolecular binding force of attraction increases as nano-sized sheets effectively disperse with the base PCM. Subsequently, thermal conductance of nano composite eutectic PCM upraised from 0.453 to 0.855 W/m⋅K. After 200 thermal cycle's chemical optical and thermal stability of the PCM composite was degraded insubstantially due to the presence of impurities with longer service; this affirmed the stability thermal perks of nanocomposite PCM. Numerical analysis on heat transfer propagation of heat source within SSD/SPDD PCM layer with and without EG nanoparticle provides inference on the importance of thermal conductivity.

Interlayer spacing control strategy to construct the rapid thermal conductivity channel in the molten salt phase change materials

With the goal of improving the thermal conductivity of inorganic salt PCMs without significantly affecting the thermal energy storage density, a functionalized modification strategy to regulate the layer spacing of nano two-dimensional (2D) materials was proposed to construct a thermal conduction pathway in phase change materials (PCMs). In the instance of graphene, we proposed hydroxylation to increase the lamellar spacing between graphene, improve its dispersion in molten salt PCMs, and speed heat transfer of graphene composite molten salt. When compared to pure graphene, the addition of hydroxylated graphene (GOH) improved the thermal conductivity of PCMs significantly. The thermal conductivity model demonstrated that the thermal conductivity pathway can be constructed by equally dispersing enough GOH to further increase the thermal conductivity. When the GOH percentage was 0.8 %, the composite's thermal conductivity was 2.60 W/(m·K), which was 118.5 % greater than the graphene composite with the same content. When the melting point was 240.00 °C, the composite material had a high latent heat of 355.52 J/g. The morphology characterization and thermal conductivity model analysis show that adjusting the layer spacing can improve graphene dispersion, facilitating the construction of thermal conduction pathway in PCMs, accelerating heat transfer, and essentially maintaining PCMs' original thermal energy storage density. Therefore, the strategy of regulating the layer spacing of 2D materials in this study has the potential to extend the application of other 2D materials used in PCMs to improve the heat storage properties.

Organic and Inorganic Hybrid Composite Phase Change Material for Inhibiting the Thermal Runaway of Lithium-Ion Batteries

To deal with the flammability of PA (paraffin), this paper proposes a CPCM (composite phase change material) with a high heat-absorbing capacity for mitigating the thermal runaway of lithium-ion batteries. Two heating power levels were used to trigger thermal runaway in order to investigate the influence of heating power on thermal runaway characteristics and the mitigation effect of the PCM (phase change material). Thermal runaway processes and temperature changes were recorded. The results showed that heating results in a violent reaction of the battery, generating a high temperature and a bright flame, and the burning of PA increases the duration of a steady flame, indicating an increased threat. SA (sodium acetate trihydrate) effectively inhibited PA combustion, and the combustion time was reduced by 40.5%. PA/SA effectively retarded the rise in temperature of the battery, and the temperature rise rate was reduced by 87.3%. Increased heating power caused faster thermal runaway, and the thermal runaway mitigation effect of the CPCM was dramatically reduced. This study may provide a reference for the safe design and improvement of thermal management systems.

Heat transfer enhanced inorganic phase change material compositing carbon nanotubes for battery thermal management and thermal runaway propagation mitigation

Developing technologies that can be applied simultaneously in battery thermal management (BTM) and thermal runaway (TR) mitigation is significant to improving the safety of lithium-ion battery systems. Inorganic phase change material (PCM) with nonflammability has the potential to achieve this dual function. This study proposed an encapsulated inorganic phase change material (EPCM) with a heat transfer enhancement for battery systems, where Na2HPO4∙12H2O was used as the core PCM encapsulated by silica and the additive of carbon nanotube (CNT) was applied to enhance the thermal conductivity. The microstructure and thermal properties of the EPCM/CNT were analyzed by a series of characterization tests. Two different incorporating methods of CNT were compared and the proper CNT adding amount was also studied. After preparation, the battery thermal management performance and TR propagation mitigation effects of EPCM/CNT were further investigated on the battery modules. The experimental results of thermal management tests showed that EPCM/CNT not only slowed down the temperature rising of the module but also improved the temperature uniformity during normal operation. The peak battery temperature decreased from 76 °C to 61.2 °C at 2 C discharge rate and the temperature difference was controlled below 3 °C. Moreover, the results of TR propagation tests demonstrated that nonflammable EPCM/CNT with good heat absorption could work as a TR barrier, which exhibited effective mitigation on TR and TR propagation. The trigger time of three cells was successfully delayed by 129, 474 and 551 s, respectively and the propagation intervals were greatly extended as well.

Thermal performance and corrosion resistance analysis of inorganic eutectic phase change material with one dimensional carbon nanomaterial

The inherent thermal characteristics, supercooling phenomenon, and corrosion issues associated with salt hydrate phase change materials (PCMs) limit their practical applications. In this research work, we report a newly formulated eutectic salt hydrate PCM using a) sodium sulphate decahydrate (SSD) & b) sodium phosphate dibasic dodecahydrate (SPDD); with a focus on customizing its properties to enhance its suitability for low temperature thermal regulation (achieving a melting point of 27.8 °C and a high heat storage capacity of 215 J/g). Additionally, we have successfully reduced the degree of supercooling and introduced corrosion resistant properties to this PCM. To enhance both the thermal energy transfer rate and optical absorbance of the eutectic PCM, we have incorporated one-dimensional (1D) multiwall carbon nanotube (MWCNT) at various weight fractions, extending up to 0.9 %, utilizing a two-step method. The dispersion and chemical stability of SSD/SPDD + MWCNT nanocomposite are verified through the morphological visual and spectral peaks obtained in Fourier transfer infrared spectroscopy. Additionally, studies evaluating the optical and thermal property reveal a substantial 500 % increase in absorbance, a notable 77.9 % reduction in transmissibility, a thermal conductivity increase from 0.464 W/m⋅K to 0.742 W/m⋅K (reflecting a 59.9 % increment), and the retention of a consistent melting enthalpy of 218.6 J/g. This stability is attributed to the intermolecular interaction with MWCNT. Similary, the degree of supercooling (ΔTs) for the SSD/SPDD EPCM containing MWCNT decreased to 2.2 °C from 16.5 °C, marking an 86 % reduction compared to the pure eutectic salt solution. Furthermore, this composite demonstrated enhanced thermal and chemical stability throughout 200 thermal cycles. Auxiliary ANSYS simulation, with transient boundary condition, are provided to analyze the heat transfer interactions between the thermic fluid and the newly developed PCM when integrated into a thermal regulation system. Subsequently, a corrosion analysis of the developed eutectic PCM and the nanocomposite eutectic PCM exhibits a corrosion rate of 0.018 mpy, well below the permissible level (<5mpy). The insights gained from the development of this nanocomposite PCM offer valuable guidance for the design and creation of tailored eutectic PCM for low-temperature thermal regulation systems, resulting in significant energy savings.