Thermal Energy Storage Applications Research Articles

Phase change-related thermal property characterization and enhancement in carbon-based organic phase change composites

By utilizing the significant amount of energy absorbed and released during their phase transitions, phase change materials (PCMs) can capture and store thermal energy to fill gaps between supply and demand. Due to their many favorable properties, organic PCMs have gained attention in a wide range of applications. Nevertheless, their inherent low thermal conductivity has limited the direct use of organic PCMs in thermal energy storage (TES). Extensive research has been conducted on enhancing organic PCM thermal conductivity by incorporating high thermal conductivity materials. Owing to their high thermal conductivity and low density, carbon-based materials have been extensively used for thermal conductivity enhancement in phase change composites (PCCs). Carbon-based organic PCCs, which incorporate highly thermally conductive carbon allotropes and their direct chemical derivatives with organic PCMs, are a group of diverse PCCs with highly promising potential for TES applications. Adequate latent heat and shape stability performances are crucial to the success of the applicational performances of these PCCs. Much empirical research has pushed efforts to enhance these phase change properties, yet a logical understanding of these enhancement efforts based on the thermodynamics and intermolecular interactions of carbon-based organic PCCs has been elusive. In particular, the effect of characterization methods on the evaluation of phase change properties has been largely understudied. This review strives to provide novel physical and chemical insights into latent heat and shape stabilization evaluation processes and enhancement efforts in carbon-based organic PCCs through a detailed review and analysis of recent literature. The review provides an unprecedented comprehension of newly developed PCCs that challenge the traditional understanding that the latent heat of PCCs cannot exceed that of its base PCM. Efforts on phase change property enhancement driven by these new insights have the potential for carbon-based organic PCCs to succeed in a variety of TES applications, including solar-thermal harvesting, thermal management of batteries and electronics, thermoregulating textiles, and infrared stealth and infrared responsive materials.

A critical review of polymer support‐based shape‐stabilized phase change materials for thermal energy storage applications

AbstractPhase change materials (PCMs) have drawn considerable attention in recent years due to their capability of storing and releasing thermal energy during phase transformation. However, traditional PCMs face challenges like limited thermal conductivity, leakage while phase transformation from solid to liquid, thermal degradation, and durability. Researchers have concentrated on creating shape‐stabilized PCMs (SSPCMs) employing polymers as the supporting matrix to overcome these difficulties and incorporating highly thermally conductive additives to improve thermal conductivity. Compared to conventional PCMs, polymer‐based SSPCMs are often more flexible, lightweight, and durable and may be easily customized according to specific applications. Various factors like PCM loading, thermal cyclability, cost‐effectiveness and environmental concerns must be considered while constructing polymer‐based SSPCMs. This review paper comprehensively explored various polymers, including polyurethane, polyacrylates, polyolefin, and so on, as promising supporting materials for SSPCMs due to their relatively high mechanical strength, compatibility with PCM, excellent thermal stability, and chemical resistance. Natural polymers like chitosan, cellulose, and starch are also considered for eco‐friendly solutions. We have also discussed about specific properties of each polymer, their cost‐effectiveness, and the environmental impact while developing such SSPCMs to guide researchers in material selection. Applications of polymer‐based SSPCMs in solar energy storage, medical devices, building materials, electronics, transportation industry, and waste heat recovery are briefly discussed. Finally, some future development areas have been discussed to attract the attention of new researchers in this field. The information provided in this review will assist readers in understanding polymer‐based SSPCM and selecting their desired polymer for support material with diverse application methods.

Functional Soft Materials with Resistance to Liquid Leakage for Thermal Energy Storage

AbstractFunctional soft materials have great potential commercial applications in thermal energy storage, which are required to have a long life, good flexibility, and resistance to liquid leakage. Herein, a composite hydrogel with thermal storage properties is prepared through coupling molecular self‐assembly and in situ polymerization. Hydrophobic stearic acid (SA), as a thermal storage phase change material (PCM), is dispersed in polyacrylamide (PAM) hydrogel network in the form of oil–water emulsion (O/W). The PAM polymer network with good flexibility physically limits high‐frequency collision between SA PCM droplets. This unique design avoids demulsification in phase change emulsion so that the as‐prepared hydrogel composite can resist liquid leakage. The PAM hydrogel network plays the role of heterogeneous nucleation, resulting in the super‐cooling of SA emulsion at only 0.3 °C. On the other hand, SA PCM droplets in as‐prepared soft material do not directly contact with liquid water, so melting/crystallization process is independent of water. As a result, the soft material exhibits a thermal storage density of up to 99.3 J g−1. The present study is an important step toward designing soft energy storage materials.

Thermo‐physical characterisation of natural rocks and impact analysis of variations in their thermo‐physical properties on thermal storage performance

AbstractIn this study, the thermal characterisation of natural rock samples from Zimbabwe for low‐temperature industrial thermal energy storage (TES) applications was carried out. Thermal stability, specific heat capacity, thermal diffusivity, thermal conductivity and density were determined. Variations in these parameters were evaluated and their impact on thermal storage performance was analysed. Basalt and dolerite samples from different locations were found to have average specific heat capacities of 826 and 853 J/kg K, respectively, at room temperature. Insignificant variations were observed with differences of 3.4% for basalt and 1.7% for dolerite samples. Also, negligible differences of 0.3% and 0.7% in densities for rocks of the same type but of different origins were obtained for basalt and dolerite samples, respectively. However, significant variations in thermal diffusivity of all the igneous and metamorphic samples were observed with quartzite rock exhibiting the highest value of 2.1 × 10−6 m2/s, while the values for the other samples range from 0.9 × 10−6 to 1.6 × 10−6 m2/s. This implies that the thermal efficiency of sensible TES systems that use different or the same rock types from different locations can be significantly high to be overlooked. Thermo‐gravimetric analysis results revealed that the rock samples studied have good thermal stability for low‐temperature heat storage applications.

Thermophysical characterization and reliability analysis of binary composite nano doping on stearic acid-acetamide eutectic PCM

Organic phase change materials (PCM) have been extensively studied and employed for thermal energy storage applications, especially in the last decade. Wide range of melting temperature with high latent heat of fusion and absence of super cooling have made them highly desirable for energy storage applications, yet their intrinsic low thermal conductivity has been a major drawback in practical implementation. This study intends to address this and study the thermophysical characteristics of an organic PCM through composite nano doping. Stearic acid-acetamide eutectic PCM with a melting temperature of 65.73 °C and a latent heat of 203.72 J/g, was incorporated with a binary blend of Aluminum Oxide nanoparticles and multi-walled carbon nanotubes (MWCNT). The addition of metallic oxide and carbonaceous nanoparticles increased the melting temperature of the eutectic mixture by 2.9 °C and a highly advantageous increment in latent heat of fusion by 10% was observed, due to the improved molecular interaction introduced by the nanoparticles. Composite nano doping enhanced the thermal conductivity of the eutectic PCM by a 132.7% and also resulted in high optical absorption properties. The prepared eutectic mixtures were chemically stable and the eutectic PCM showed an improved final degradation temperature and thermal stability, with composite nano doping. Thermal reliability was analyzed through accelerated thermal cycling test and the eutectic mixtures could retain their thermal characteristics and chemical stability even after 500 thermal cycles. Composite nano doping proved to be a reliable thermophysical characteristics enhancement technique for organic eutectic PCM.

Crystal Phase Ionic Liquids for Energy Applications: Heat Capacity Prediction via a Hybrid Group Contribution Approach.

In the selection and design of ionic liquids (ILs) for various applications, including heat transfer fluids, thermal energy storage materials, fuel cells, and solvents for chemical processes, heat capacity is a key thermodynamic property. While several attempts have been made to develop predictive models for the estimation of the heat capacity of ILs in their liquid phase, none so far have been reported for the ILs' solid crystal phase. This is particularly important for applications where ILs will be used for thermal energy storage in the solid phase. For the first time, a model has been developed and used for the prediction of crystal phase heat capacity based on extending and modifying a previously developed hybrid group contribution model (GCM) for liquid phase heat capacity. A comprehensive database of over 5000 data points with 71 unique crystal phase ILs, comprising 42 different cations and 23 different anions, was used for parameterization and testing. This hybrid model takes into account the effect of the anion core, cation core, and subgroups within cations and anions, in addition to the derived indirect parameters that reflect the effects of branching and distribution around the core of the IL. According to the results, the developed GCM can reliably predict the crystal phase heat capacity with a mean absolute percentage error of 6.78%. This study aims to fill this current gap in the literature and to enable the design of ILs for thermal energy storage and other solid phase applications.

Role of Polymers in Anchoring the Performance of Phase Change Materials for Thermal Energy Storage Applications: An Overview

Role of Polymers in Anchoring the Performance of Phase Change Materials for Thermal Energy Storage Applications: An Overview

Heat transfer study of metal foam with partial filling method to strengthen phase change material

The advancement of ice-ball thermal energy storage systems is limited by the poor thermal conductivity of phase change materials(PCM). This paper presents a numerical investigation into enhancing heat transfer in ice balls by partially filling them with metal foam. Dynamic temperature changes, solid phase fraction, and cold storage capacity are analyzed for various filling radius ratios (2/13, 4/13, 6/13, 8/13, and 13/13). We quantitatively assess the specific impact of metal foam filling on heat transfer by calculating changes in the comprehensive thermal conductivity coefficient. Our findings reveal that the comprehensive thermal conductivity coefficient increases nonlinearly with the growing metal foam filling radius ratio, indicating that full filling may not the most optimal configuration. Furthermore, the energy storage capacity per unit time, per unit weight and per unit cost of the ice ball filled with metal foam under different radius ratios was evaluated by comprehensive evaluation criteria, and the optimal filling radius ratio was determined to be 6/13. Contrary to prior findings, this research highlights the efficacy of partial filling strategies, offering valuable insights for optimizing ice ball performance in thermal energy storage applications.

Investigation on the Initial Stage of the Dehydration Process in Mg(OH)2 by Density Functional Theory Calculations.

Mg(OH)2/MgO has been attracting considerable interest as a viable candidate for thermochemical heat storage materials, particularly within the temperature range of 200-400 °C. Nonetheless, the typical dehydration temperature of Mg(OH)2, which occurs within the 300-400 °C range, needs to be reduced to enhance its effectiveness in various applications for thermal energy storage. While several studies have shown that heterospecies doping can lower the dehydration temperature, the fundamental mechanism underlying this effect still remains unclear. Here, we employed density functional theory calculations to elucidate the dehydration mechanism of Mg(OH)2, with a particular focus on the initial stage of the dehydration that determines the temperature beginning the reaction. Our findings indicate that the formation of water molecules on the (001) surface is critical in the early stages of the dehydration. This discovery provides a comprehensive explanation for the role of dopants (Na, Li, or LiCl) in reducing the dehydration temperature by decreasing the formation energy of paired H and OH defects and the migration barrier of H on the surface. The present study will significantly advance the development of novel dopants for Mg(OH)2, facilitating a lower dehydration temperature and, thereby, increasing its suitability for heat storage applications.

Preparation and characterization of eicosane-paraffin/expanded graphite/polyurethane as form-stable composite phase change materials with wide phase change temperature range

Phase change materials (PCMs) with wide phase change temperature range, high latent heat, good thermal conductivity, and shape stability are essential for applications such as solar energy conservation and thermal management of electronic devices. Form-stable composite PCMs (FSCPCMs) with a broad phase change temperature range of 18–65 °C were successfully developed by using a mixture of eicosane and paraffin mixture along with cross-linking polyurethane as PCM, expanded graphite as thermally conductive filler and supporting material. The prepared FSCPCMs demonstrated excellent thermal stability and thermal conductivity with a latent heat up to 142.5 J/g. In conclusion, the synthesized FSCPCMs exhibit promising potential for practical applications in thermal energy storage.

Research Progress of Photovoltaic Cooling Systems Based on Phase Change Materials: An Overview

Photovoltaic technology plays a crucial role in harnessing renewable energy. While photovoltaic panels directly convert solar energy into electricity, more than 50% of solar radiation is lost as waste heat, diminishing the overall efficiency of the panels. This study reviews various cooling technologies for photovoltaic systems, focusing on the use of phase change materials for cooling in photovoltaic systems. Phase change materials, known for their high latent heat capacity, are extensively used in thermal energy storage applications. Incorporating phase change materials in photovoltaic systems can increase thermal storage potential by 30–50% compared to conventional systems, leading to a 70% extension in heat storage duration and various levels of enhanced power output. The main purpose of the article is to review the advantages and disadvantages of various technologies, determine the research direction of phase change materials for cooling systems in photovoltaics, and ensure the reliability of this technology.

Shape-stable phase change materials based on carboxymethyl chitosan/boron nitride nanosheets high-strength aerogel

The application of phase change materials (PCMs) in energy storage and temperature control systems holds significant promise for enhancing energy efficiency and environmental sustainability. Herein, the development of a boron nitride nano-aerogel-supported PCM, reinforced by carboxymethyl chitosan (CMCS) and oxidized corn starch (DCS) cross-linking was reported. This approach involved the utilization of polydopamine-modified boron nitride nanosheets (PDA@BNNS) for the fabrication of a thermally conductive skeleton, while carboxymethyl chitosan (CMCS) and oxidized corn starch (DCS) were utilized as reinforcing material and cross-linking agent, respectively. The skeleton was prepared via a sol-gel method and freeze-drying technique, while polyethylene glycol (PEG) was subsequently encapsulated using a vacuum impregnation method. Notably, the prepared skeleton exhibits a compressive stress of 12.18 MPa at 80 % strain, much higher than other boron nitride nanosheets aerogels reported in literature. The cross-linked boron nitride skeleton enhances the thermal conductivity of the composites by 137.4 % compared to pure PEG. Furthermore, due to the highly porous structure of the skeleton, the PEG mass fraction reaches 96.0 wt%, resulting in a phase change enthalpy of 181.5 J/g. The results suggest that this composite material is a promising PCM candidate for thermal energy storage applications.

Development and comparison of multi-walled carbon nanotubes and graphite nanoflakes dispersed solar salt: Structural formation and thermophysical properties

A molten salt energy storage has proven to be a promising candidate for medium and high-temperature thermal energy storage (TES) applications. Improving the thermophysical properties, such as specific heat capacity (Cp) and thermal conductivity (k) is crucial to deciding the charging/discharging characteristics of the energy storage system. In this study, 1 wt% of two variant carbon allotropes, such as multi-walled carbon nanotubes (MWCNTs) and graphite nanoflakes (GNFs), were dispersed in solar salt (i.e., MWCNTs nanosalt and GNFs nanosalt) using wet preparation method. Thermophysical properties of the prepared nanosalts were evaluated using different analytical techniques and compared with pristine solar salt. The specific heat capacity was measured from 50 °C to 350 °C, and the maximum specific heat capacity enhancement in 1 wt% of MWCNTs dispersed solar salt was 18 %. The enhancement in 1 wt% of GNFs dispersed solar salt was 12.5 % at 200 °C (in solid phase). Similarly, in the liquid phase (at 350 °C), MWCNTs dispersed solar salt improves Cp by 6.2 %, while GNFs dispersed solar salt exhibits negligible improvement in Cp. Further, a modified transient plane source (MTPS) technique was used to measure the thermal conductivity of both carbon nanosalts in the solid phase (30–100 °C). The maximum thermal conductivity enhancement observed for MWCNTs dispersed solar salt and GNFs dispersed solar salt was 5.8 % and 11.7 %. Finally, thermogravimetric analysis was conducted to evaluate the thermal stability of the MWCNTs nanosalt and GNFs nanosalt at a maximum temperature of 700 °C, and found that the MWCNTs nanosalt show better thermal stability than the GNFs nanosalt.

Numerical modelling and experimental validation on the discharging performance of paraffin/graphite matrix composite with various configurations of bulk density and wall temperature

Graphite material in the form of expanded has proven to be an effective material to remedy the low thermal conductivity of paraffin storage medium. The present work focuses on the solidification performance of carbon-based approach via graphite matrix composite with phase change to eliminate the bottleneck of low thermal conductivity issue of phase change materials for thermal energy storage applications beyond the current literature. Paraffin/graphite matrix composites with various bulk density values of 0 kg/m3 (Case 1), 23 kg/m3 (Case 2), 50 kg/m3 (Case 3), 100 kg/m3 (Case 4), and 143 kg/m3 (Case 5) under various operating conditions of wall temperature (Twall: 15 °C, 25 °C, 35 °C, and 45 °C), which mimic real applications' fluid temperature, are performed numerically in detail. The numerical model was validated with experimental outputs performed by the authors. Numerical results show that paraffin/graphite matrix composites have a great potential for the solidification/discharging process to recover the heat stored in the charging/melting period. Uniform and rapid solidification behaviour is achieved with the paraffin/graphite matrix composite in terms of conduction-dominated heat transfer via abundant thermal bridges compared to the pure paraffin case. Higher bulk density values and lower cold surface temperatures present superior performance in solidification rate and thermal energy recovery rate. However, the effect of the bulk density is slowed down with the beyond of certain value of bulk density (100 kg/m3). For 100 kg/m3 (Case 4) at Twall = 15 °C, the heat recovery rate is enhanced by 31.17 times and 3.84 times compared to the 0 kg/m3 and 23 kg/m3. The heat recovery rate of 100 kg/m3 is improved by 350.8 % for Twall = 15 °C in comparison with Twall = 45 °C. The total solidification rate (t = 17.5 min) increased by 90.94 % and 62.94 % for 100 kg/m3 at Twall = 35 °C compared to 0 kg/m3 and 23 kg/m3, respectively.

A novel PCM/expanded graphite composite sphere with high thermal conductivity and excellent shape stability used for a packed-bed thermal energy system

In this research, a novel phase change material (NPCM) sphere was developed and its application in a packed-bed thermal energy storage (PBTES) system during thermal energy storage was studied. Paraffin wax (PW) with a melting point of 40 °C was selected as phase change material (PCM), expanded graphite (EG) as thermal conductivity enhancement material, and epoxy resin (ER) as a surface coating. The results show that the three-dimensional heat conduction network constructed by EG foam improves the thermal conductivity of PW/EG. The thermal conductivity of NPCM is anisotropic. The thermal conductivities perpendicular and parallel to the EG compression direction are 9.03 (W/m·K) and 5.58 W/(m·K). NPCM has excellent shape stability with a leakage rate of only 2.95 %. Then, a PBTE system was built to record the temperature evolution of NPCM spheres at various inlet temperatures and volume flow rates during thermal energy storage, and thermodynamic analysis was performed. The results are as follows. (1) The temperature of the NPCM sphere near the inlet rises more rapidly and the melting time of PCM is shorter. (2) Increasing the inlet temperature improves the heat transfer and shortens the melting time of PCM while increasing the temperature inhomogeneity of the NPCM spheres. Increasing the inlet temperature increases the energy storage capacity. However, higher inlet temperature leads to lower energy efficiency and exergy efficiency. The energy efficiency and exergy efficiency are 49.66 % and 67.64 % for the inlet temperature of 60 °C, respectively. When the inlet temperature increases from 60 °C to 80 °C, the energy efficiency and exergy efficiency decrease by 16.13 % and 16.22 %, respectively. (3) Higher inlet volume flow rate also promotes heat transfer and reduces the melting time of the PCM, but has little effect on the temperature inhomogeneity of the NPCM spheres. Increasing the inlet volume flow rate does not increase the energy storage capacity. Similarly, increasing the inlet volume flow rate also results in a decrease in energy efficiency and exergy efficiency. At the inlet volume flow rate of 19.28 m3/h, the energy efficiency and exergy efficiency are 41.65 % and 56.67 %, respectively. When the inlet volume flow rate increases from 19.28 m3/h to 25.16 m3/h, the energy efficiency reduces by 7.80 % while the exergy efficiency reduces by 7.41 %. This research provides a foundation for the application of the NPCM sphere.

Nanoscale Stabilization Mechanism of Sodium Sulfate Decahydrate at Polyelectrolyte Interfaces.

Sodium sulfate decahydrate (SSD) is a low-cost phase-change material (PCM) for thermal energy storage applications that offers substantial melting enthalpy and a suitable temperature range for near-ambient applications. However, SSD's consistent phase separation with decreased melting enthalpy over repeated thermal cycles limits its application as a PCM. Sulfonated polyelectrolytes, such as dextran sulfate sodium (DSS), have shown great effectiveness in preventing phase separation in SSD. However, there is limited understanding of the stabilization mechanism of SSD by DSS at the atomic length and time scales. In this work, we investigate SSD stabilization via DSS using neutron scattering and molecular dynamics (MD) simulations. Neutron scattering and pair distribution function analysis revealed the structural evolution of the PCM samples below and above the phase change temperatures. MD simulations revealed that water from the hydrate structure migrates from the hydrate crystal to the SSD-DSS interfacial region upon melting. The water is stabilized at this interface by aggregation around the hydrophilic sulfonic acid groups attached to the backbone of the polyelectrolyte. This architecture retains water near the dehydrated sodium sulfate, preventing phase separation and, consequently, stabilizing SSD rehydration. This work provides atomistic insight into selecting and designing stable and high-performance PCMs for heating and cooling applications in building technologies.

Indium-Mediated Acyloxyallylation-Based Synthesis of Galacto-Configured Higher-Carbon Sugar Alcohols as Potential Phase Change Materials.

Sugar alcohols fulfilling specific structural requirements are a substance class with great potential as organic phase change materials (PCMs). Within this work, we demonstrate the indium-mediated acyloxyallylation (IMA) as a useful strategy for the synthesis of higher-carbon sugar alcohols of the galacto-family featuring all hydroxyl groups in a 1,3-anti-relationship with three major synthetic achievements: first, the dihydroxylation of the IMA-derived allylic sugar derivates was systematically studied in terms of diastereoselectivity, revealing a high degree of substrate control toward anti-addition. Second, we demonstrated the use of a "double Mitsunobu" reaction, inverting the stereochemistry of terminal diols. Third, the IMA toolbox was expanded to accomplish the synthesis of derivatives with up to 10 carbon atoms from particularly unreactive aldoses. Thermal investigations of all synthesized sugar alcohols, including examples with exclusive 1,3-anti- and suboptimal 1,3-syn-relationships as well as even and odd numbers of carbon atoms, were performed. We observed clear trends in melting points and thermal storage densities and discovered limitations of organic substances in this class with melting points above 240 °C as PCMs in terms of thermal stability. With our study, we provide insights into the dependence of thermal properties on structural features, thus contributing to further understanding of organic PCMs for thermal energy storage applications.

Form-stable Na2CO3-NaCl/mullite phase change composite with SiC enhanced thermal conductivity for high temperature thermal storage

High-temperature energy storage technologies are gaining prominence to meet the needs of concentrating solar power plants and industrial waste heat recovery. In this study a series of form-stable phase change materials are prepared by a simple and efficient cold compression sintering method. In this method, Na2CO3-NaCl will be mixed with mullite ceramic powder; simultaneously, SiC nanoparticles are introduced to improve the thermal conductivity of the material. The leakage, microstructure, chemical compatibility and thermal physical properties of the prepared composites are systematically analyzed using Fourier-transform infrared spectroscopy, X-ray powder diffraction, Scanning electron microscope, Differential Scanning Calorimetry and Thermogravimetric. The results of the study show that good chemical compatibility of the components in the composites, and the latent heat of melting of the encapsulated composites as well as the sample with added SiC are 266.97 J/g and 217.63 J/g, respectively, while the latent heat of crystallization is 197.37 J/g and 151.13 J/g, respectively. Compared to the thermal conductivity of PCMs (0.41 W/(m·K)), the thermal conductivity of the sample with 20 % SiC added is 1.83 W/(m·K), an increase of 8.7 times. Thermal cycling and reliability tests show that even after 300 cycles, good chemical compatibility is maintained between the components in composites, and the phase change properties and quality remain stable. In addition, the thermal storage cost of FSPCM-M40-S20 is 1.90 $/MJ. Therefore, we believe that the prepared Na2CO3-NaCl/mullite/SiC FSPCM has promising applications in high-temperature thermal energy storage, especially in solar power generation and industrial waste heat recovery.

Review on thermal properties and reaction kinetics of Ca(OH)2/CaO thermochemical energy storage materials

AbstractThermochemical energy storage technology is one of the most promising thermal storage technologies, which exhibits high energy storage capacity and long‐term energy storage potentials. The low‐cost, safe, and reliable calcium oxide/calcium hydroxide (CaO/Ca(OH)2) system has become the preferred thermochemical energy storage material system to solve the problem of renewable energy consumption. This study reviews the structural, thermodynamic, and kinetic properties influencing the absorption and desorption reactions of calcium oxide (CaO) and calcium hydroxide (Ca(OH)2) in thermal energy storage applications. It is found that the transformation of crystal structure from cubic to hexagonal upon hydration is attributed to volume expansion and crack formation facilitating diffusion. The specific heat capacities of CaO and Ca(OH)2, as well as reaction enthalpies, are studied across temperature ranges. Most studies on reaction kinetics are focused on the effect of factors such as temperature, particle size, and material content. Strategies to mitigate issues such as particle agglomeration and enhance reaction efficiency are discussed, including the incorporation of enhancing materials such as γ‐Al2O3. This study underscores the importance of the core reaction material content and the enhancing materials that are used to optimise energy density in thermal chemical water‐absorption and ‐desorption reactions.

Silica-Derived Nanostructured Electrode Materials for ORR, OER, HER, CO2RR Electrocatalysis, and Energy Storage Applications: A Review.

Silica-derived nanostructured catalysts (SDNCs) are a class of materials synthesized using nanocasting and templating techniques, which involve the sacrificial removal of a silica template to generate highly porous nanostructured materials. The surface of these nanostructures is functionalized with a variety of electrocatalytically active metal and non-metal atoms. SDNCs have attracted considerable attention due to their unique physicochemical properties, tunable electronic configuration, and microstructure. These properties make them highly efficient catalysts and promising electrode materials for next generation electrocatalysis, energy conversion, and energy storage technologies. The continued development of SDNCs is likely to lead to new and improved electrocatalysts and electrode materials. This review article provides a comprehensive overview of the recent advances in the development of SDNCs for electrocatalysis and energy storage applications. It analyzes 337,061 research articles published in the Web of Science (WoS) database up to December 2022 using the keywords "silica", "electrocatalysts", "ORR", "OER", "HER", "HOR", "CO2RR", "batteries", and "supercapacitors". The review discusses the application of SDNCs for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), carbon dioxide reduction reaction (CO2RR), supercapacitors, lithium-ion batteries, and thermal energy storage applications. It concludes by discussing the advantages and limitations of SDNCs for energy applications.