Thermal Cycling Stability Research Articles

Processing and properties of Al–Si microcapsules with a biomimetic-corrugated structure and corundum-mullite composite shell

The encapsulation of metal-based phase change materials using ceramics can realize safe and effective storage of high-temperature thermal energy. However, the use of a low toughness ceramic shell around the microcapsules cannot ensure the provision of a high latent heat and thermal cyclic stability. Here, we provide a new and effective design strategy for preparing biomimetic Al–Si microcapsules that are based on a sea-shell corrugated structure and a nano-scale corundum-mullite composite shell. The latent heat of the microcapsules was over 400 J/g, much greater than other metal-based microcapsules reported to date. The unique biomimetic-corrugated structure microcapsules obtained by a heat treatment at 1000 °C exhibited excellent thermal stability, achieving near zero heat loss after 5000 thermal cycles, whose latent heat of absorption and release reached up to 448.3 J/g and 451.8 J/g respectively. Furthermore, the microcapsules possessed a giant heat storage density of 945.8 J/g within 300–700 °C, and the performance figure of merit was 6384.2 × 106 J2·K–1·s–1·m–4, approximately 15 times higher than that of commercial solar salt. This new approach provides a pathway the practical application of Al–Si alloys as thermal storage materials for renewable energy applications.

Enhanced thermal cycle stability and shape memory effect in NiTiHf shape memory alloys fabricated by laser powder bed fusion

We report on the fabrication of NiTiHf high temperature shape memory alloys (SMAs) via laser powder bed fusion (LPBF), which are almost free of micro-pores and display (Ti, Hf)2Ni nanoprecipitates with variable size and volume fraction. The effect of variable laser powers of 50 W, 60 W and 70 W on the martensite variant microstructures and mechanical properties of the LPBFed SMAs was investigated. Interestingly, all LPBFed NiTiHf samples display enhanced thermal cycle stability of transformation temperatures with a temperature eviation of −3°C, which is attributed to the lack of dislocation slip originated from the habit plane configuration characteristic with multidomain (001) martensite compound twins. Meanwhile, all LPBFed NiTiHf samples exhibit trained one-way and two-way shape memory effects due to the dislocation slip upon compression deformation at room temperature.

Challenges and Advancements in the Electrochemical Utilization of Ammonia Using Solid Oxide Fuel Cells.

Solid oxide fuel cells utilized with NH3 (NH3-SOFCs) have great potential to be environmentally friendly devices with high efficiency and energy density. The advancement of this technology is hindered by the sluggish kinetics of chemical or electrochemical processes occurring on anodes/catalysts. Extensive efforts have been devoted to developing efficient and durable anode/catalysts in recent decades. Although modifications to the structure, composition, and morphology of anodes or catalysts are effective, the mechanistic understandings of performance improvements or degradations remain incompletely understood. This review informatively commences by summarizing existing reports on the progress of NH3-SOFCs. It subsequently outlines the influence of factors on the performance of NH3-SOFCs. The degradation mechanisms of the cells/systems are also reviewed. Lastly, the persistent challenges in designing highly efficient electrodes/catalysts for low-temperature NH3-SOFCs, and future perspectives derived from SOFCs are discussed. Notably, durability, thermal cycling stability, and power density are identified as crucial indicators for enhancing low-temperature (550°C or below) NH3-SOFCs. This review aims to offer an updated overview of how catalysts/electrodes affect electrochemical activity and durability, offering critical insights for improving performance and mechanistic understanding, as well as establishing the scientific foundation for the design of electrodes for NH3-SOFCs.

A comprehensive analysis of cermet design and thermal cyclic stability via elasto-viscoplastic crystal plasticity modeling

Ceramic-metal composites, or cermets, exhibit beneficial properties resulting in their use in many industrial applications. One challenge with cermets is mismatches in the coefficient of thermal expansion (CTE) values between the ceramic and metal phases that lead to residual stresses after processing, plasticity in the metal phase, internal stresses, and instability after thermal cycling. In order to make predictions of these properties to inform the design of cermets, we employ an incremental elasto-viscoplastic, self-consistent formulation to calculate the thermal, elastic, and plastic strains in two-phase polycrystalline cermet materials. This framework is extended to include temperature dependent properties, which are called implicitly within the temperature-dependent, incremental elasto-viscoplastic, self-consistent (TE-VPSC) model. Temperature-induced cooling and thermal cycling simulations are conducted using the TE-VPSC framework to study the residual stresses and plastic strains in the metal phases. Two materials are discussed in detail exhibiting stark differences based on the CTE between their ceramic and metal phases, WC/57-vol% Cu (exhibiting a pronounced CTE mismatch) and Y2O3/27-vol% Nb (exhibiting a negligible CTE mismatch). The model demonstrates high residual stresses in the Cu phase during processing and reverse plasticity leading to recovery of plastic strain during thermal cycling of the WC/Cu cermet. Moreover, the model demonstrates relatively low residual stresses and plasticity in Y2O3/Nb and a thermal stability point of 1251 °C, below which no plasticity develops in the cermet. We employ the TE-VPSC model as a design tool for cermets to systematically investigate the effects of process-induced microstructure variations (volume fraction, grain aspect ratio, and crystallographic texture are investigated) and compositional differences (19 compositions are explored) on the residual stress, degree of plasticity in the metal phase, and thermal stability point. The computational efficiency of the TE-VPSC framework makes it a desktop design tool that can be used to quantify the impact of changing composition, processing, and thermo-mechanical loading on the performance of the cermet, which can help reduce the number of time intensive and costly high temperature experiments.

Multifunctional phase change film with high recyclability, adjustable thermal responsiveness, and intrinsic self-healing ability for thermal energy storage

Phase change materials (PCMs) present promising potential for guaranteeing safety in thermal management systems. However, most reported PCMs have a single application in energy storage for thermal management systems, which does not meet the growing demand for multi-functional materials. In this paper, the flexible material and hydrogen-bonding function are innovatively combined to design and prepare a novel multi-functional flexible phase change film (PPL). The 0.2PPL-2 film exhibits solid-solid phase change behavior with energy storage density of 131.8 J/g at the transition temperature of 42.1 °C, thermal cycling stability (500 cycles), wide-temperature range flexibility (0–60 °C) and self-healing property. Notably, the PPL film can be recycled up to 98.5% by intrinsic remodeling. Moreover, the PPL film can be tailored to the desired colors and configurations and can be cleverly assembled on several thermal management systems at ambient temperature through its flexibility combined with shape-memory properties. More interestingly, the transmittance of PPL will be altered when the ambient temperature changes (60 °C), conveying a clear thermal signal. Finally, the thermal energy storage performance of the PPL film is successfully tested by human thermotherapy and electronic device temperature control experiments. The proposed functional integration strategy provides innovative ideas to design PCMs for multifunctionality, and makes significant contributions in green chemistry, high-efficiency thermal management, and energy sustainability.

A novel approach for brazing MgF2 ceramic to TA15 alloy using AgCu/GH4169/Bi2O3[sbnd]B2O3[sbnd]ZnO composite braze fillers

A two-step brazing process was successfully employed to join MgF2 ceramic and TA15 alloy using eutectic Ag28% (in mass fraction) Cu alloy and Bi2O3B2O3ZnO (BBZ) glass as fillers, by introducing a 100 μm thick GH4169 interlayer. Multiscale characterization revealed that interdiffusion and reaction occurred at the joint interfaces. As a result, a reliable joint system consisting of TA15/TiCu/TiCu2Al/Ag(s,s) + Cu(s,s)/TiCu2Al/TiCu Ni + Ag-rich layer/GH4169/nano-oxide layer/glass/Mg3(BO3)F3+MgO + MgF2 reaction layer/MgF2 was formed. The GH4169-interlayer exhibited adaptive compatibility though its interaction with AgCu and BBZ glass fillers, effectively accommodating strong interface bonding and thermal mismatch stress between TA15 and MgF2 substrates. It shows an excellent shear strength (32 MPa, at room temperature) as well as thermal cycling stability without any cracking or spallation observed after the 20 thermal shock cycles between room temperature and 300 °C. It provides valuable insights into designing highly reliable ceramic/metal joints that demonstrate superior stability and adaptability in specific applications.

Revealing the Role of Polyacrylonitrile for Highly Efficient and Stable Perovskite Solar Cells at Extremely Low Temperatures

AbstractPerovskite solar cells (PSCs) are considered to be a promising candidate for near‐space applications due to their high specific power, excellent radiation resistance, and compatibility with flexible substrates. Nevertheless, the low‐temperature cycles impose considerable challenges to their long‐term stability. Herein, the extremely low‐temperature photovoltaic process of PSCs is investigated and the effect mechanisms of PAN (Polyacrylonitrile) as an additive are revealed. It is found that the additive PAN regulates perovskite lattice stress and stabilizes perovskite lattice structure and thus retards perovskite phase transition at low temperatures. Moreover, the PAN improves perovskite dielectric properties and ion migration activation energy and effectively passivates perovskite defects at low temperatures. Therefore, the carrier transport/extraction/collection abilities at low temperatures are enhanced effectively by alleviating exciton effect and increasing dielectric screening effect. Benefiting from these positive effects of PAN, the PAN‐modified device achieves a maximum efficiency of 24.34% at 150K and maintains 72% of its initial value after 120 thermal cycles (290‐130K). Also, the PAN‐modified flexible devices exhibit excellent bending stability and thermal cycle stability. This study provides a deep insight into understanding the extremely low‐temperature photovoltaic behavior of PSCs and demonstrates the potentiality of PAN additive strategy for achieving efficient and stable PSCs at low temperatures.

A Manufacturing Method for High-Reliability Multilayer Flexible Electronics by Electrohydrodynamic Printing

To meet the demand for higher performance and wearability, integrated circuits are developing towards having multilayered structures and greater flexibility. However, traditional circuit fabrication methods using etching and lamination processes are not compatible with flexible substrates. As a non-contact printing method in additive manufacturing, electrohydrodynamic printing possesses advantages such as environmental friendliness, sub-micron manufacturing, and the capability for flexible substrates. However, the interconnection and insulation of different conductive layers become significant challenges. This study took composite silver ink as a conductive material to fabricate a circuit via electrohydrodynamic printing, applied polyimide spraying to achieve interlayer insulation, and drilled micro through-holes to achieve interlayer interconnection. A 200 × 200 mm2 ten-layer flexible circuit was thus prepared. Furthermore, we combined a finite element simulation with reliability experiments, and the prepared ten-layer circuit was found to have excellent bending resistance and thermal cycling stability. This study provides a new method for the manufacturing of low-cost, large-sized, multilayer flexible circuits, which can improve circuit performance and boost the development of printed electronics.

Performance and Phase Change Kinetic Investigations on Capric-Myristic Acid Eutectic Mixtures for Energy-Saving Construction

In the present study, capric acid and myrisic acid were first selected to prepare a capric acid-myrisic acid eutectic mixture using a compounding method. Then, the thermal properties, structural stability and weight loss of capric acid-myrisic acid eutectic mixtures were analyzed using differential scanning calorimetry, Fourier transform infrared and thermogravimetry. Finally, the activation energy and reaction order of the capric acid-myrisic acid eutectic mixture during solid-liquid transformation were calculated using the phase change kinetic methods of Kissinger and Ozawa. The results indicate that capric acid-myrisic acid eutectic mixtures have good thermal cycle stability and stable energy storage in practical applications. The activation energies of capric acid-myrisic acid eutectic mixtures were calculated using the phase change kinetic methods of Kissinger and Ozawa, with values of 345.6 KJ/mol and 333.3 KJ/mol, respectively, indicating that both phase change kinetic methods have good accuracy.

Thermal Cycling Stability of Ti-Zr-Nb-Al Shape Memory Alloy

Shape memory alloys, as a novel class of intelligent materials, possess substantial application potential in the field of petroleum engineering at elevated temperatures. However, the complex downhole environment necessitates the alloy to endure alternating cycles of cold and heat, demanding both a high phase transformation temperature and excellent thermal cycling stability. This study focuses on a quaternary Ti-Zr-Nb-Al shape memory alloy, examining the thermal cycling stability of the Ti-20Zr-10Nb-xAl (x=1, 2, 3, 4 at%) alloys after subjecting them to 50 thermal cycles. Results indicate that the alloy composition, post 50 cycles, transitions from a single martensite α'' -phase to a duplex microstructure comprising α''-phase and β-phase. Changes in Al content did not significantly affect the phase composition of the alloy in its thermally cycled state. As Al content increases, both the tensile strength and shape memory effect of the alloy initially improve before declining. In terms of shape memory properties, the Ti-20Zr-10Nb-2Al alloy sample exhibits the most favorable thermal cycling stability, characterized by a tensile strength of 692 MPa, an elongation of 6%, a shape memory effect of 0.96% under 4% pre-strain, a shape memory recovery rate of 38%, and a Vickers microhardness of 381 HV.

Improved length of calcium sulfate crystal seeds and whiskers via ball milling and hydration treatment

Elucidating the effect of growth periods on the quality of calcium sulfate whiskers (CSWs) prepared from calcium sulfate dihydrate (DH) is imperative. Herein, crystal seeds and whiskers were prepared from DH in a water–glycerol system. Longer whiskers were obtained from crystal seeds prepared via hydration of DH for 30 s than via ball milling for 5 min followed by hydration for 20 s. The attachment of cetyltrimethyl ammonium bromide and glycerol additives to the whisker tops promoted whisker growth. The whisker sponges exhibited good thermal barrier properties and compression cycle stability.

Thermal cycle stability and microstructure of Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals

The Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) ferroelectric single crystals have been commercially available as important components in medical ultrasound transducers due to their excellent piezoelectric and electromechanical coupling performance. The variation in piezoelectric and dielectric properties of PMN-PT single crystals with ambient temperature is an important application indicator. In this work, the PMN-PT single crystals after direct current poling (DCP) and alternating current poling (ACP) were subjected to the cyclic thermal treatment process. The thermal cycling stability and microstructural changes in PMN-PT single crystals were investigated. The ACP single crystals exhibit a higher dielectric constant ε33T/ε0 (6500–7600) and piezoelectric coefficient d33 (2100–2500 pC N−1) compared to the DCP single crystals (ε33T/ε0 of 4100–5000, d33 of 1200–1300 pC N−1). Under thermal cycling at 60 °C, the DCP and ACP single crystals exhibit good thermal cycling stability after 150 cycles. Microstructural observations show that the domain structure of the DCP single crystals exhibits “staggered domain walls, inhomogeneous domain size, variety of domain structure,” while the relatively homogeneous stripe-like domains were observed in the ACP single crystals. After thermal cycling, new fine striped domains appear in both the DCP and ACP single crystals due to the instability of rotated polarization, but the piezoelectric and dielectric properties are not greatly affected. This work provides an intensive understanding of the effects of thermal cycling on the domain structure, which is useful for applications.

Radial assembly of graphene nanoplates via ice-template method to construct 3D thermally conductive phase change materials

Phase change material (PCM) with the capacity to store and release substantial thermal energy, has drawn significant attention. However, its large-scale application is still hindered by inadequate thermal management capacity and unsatisfactory thermal conductivity. In this study, graphene nanoplates were assembled into a 3D thermally conductive scaffold using a specialized ice template method. By virtue of the unique growth of ice crystals in radial pattern, a series of multidirectional thermal conduction pathways were successfully constructed within PCM, which has provided microscopically interconnected pathways for thermal transport. Consequently, a remarkable 5.2-fold increment in thermal conductivity (1.365 W m−1 K−1) in comparison to pure paraffin was achieved by incorporating a mere 6 vol% of GNP, which therefore enables excellent thermal cycling stability, remarkable latent heat storage capacity exceeding 175 J/g, together with leak-proof properties even under extended high-temperature conditions. Moreover, the solar-to-thermal energy storage efficiency is up to 85.8 % due to its efficient photothermal effect. This work presents an innovative approach to design PCMs with enhanced thermal conductivity and photothermal efficiency, offering promising applications in advanced thermal storage.

Thermal properties analysis and thermal cycling of HITEC molten salt with h-BN nanoparticles for CSP thermal energy storage applications.

Molten salts are the operational fluid for most concentrated solar power (CSP) systems, which has attracted more attention among the scientific community due to the augmentation of their properties with the doping of nanoparticles. Hexagonal boron nitride (h-BN) nanoparticles were dispersed in HITEC molten salt to create a novel nanofluid and evaluate the h-BN nanoparticles' influence on HITEC thermophysical properties. The influence of nanoparticle concentration (0.1, 0.5, and 1wt.%) of h-BN and HITEC was studied in this research. HITEC and nano-enhanced HITEC molten salt (NEHMS) were characterized using energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FT-IR). Specific heat capacity, latent heat, and melting temperature were assessed using differential scanning calorimetry (DSC). The maximum working temperature was evaluated with thermogravimetric analysis (TGA). The ideal nanoparticle concentration is 0.1 wt.% h-BN, which results in a 27% increase in heat capacity, a 72% increase in latent heat, and a 7% enhancement in thermal stability. The thermal cycling stability test proved the stability of the enhanced thermophysical properties. The material characterization revealed that the samples with improved thermophysical properties have a homogeneous dispersion of nanoparticles with minor nanoparticle agglomeration. The system advisor model (SAM) simulation comparison of the optimum sample with solar salt and HITEC salt revealed that using the optimum sample increases CSP plant efficiency by 0.4% and reduces power costs by 0.13¢/kWh.

Stabilizing Layered‐Type K0.4V2O5 Cathode by K Site Substitution with Strontium for K‐Ion Batteries

AbstractDeveloping suitable cathodes with high capacity and high power is challenging for K‐ion batteries. Herein, electrochemical K‐ion storage properties of the layered‐type K0.4V2O5 (KVO) cathode by incorporating divalent strontium ions (Sr2+) into its crystal structure are enhanced. Divalent strontium ions (1.18 Å) are preferentially incorporated into the octahedrally coordinated K (1.38 Å) layers due to the similar ionic size compared to V4+ (0.58 Å). The introduction of 3 mmol of Sr ions in the KVO crystal improves electrical conductivity and reduces K‐ion diffusion energy barriers. In addition, the strong Sr2+ and O2− interaction acts as a structural pillar, suppressing irreversible phase transition during charge–discharge process. Multi‐physics simulations clearly confirm that the K0.34Sr0.03V2O5 (KS3VO) cathode exhibits a more uniform K‐ion distribution and enhanced reactions of K‐ions compared to the KVO cathode at various depths of discharge. As a result, the KS3VO cathode demonstrates improved reversible capacity, cycling stability, and power capability over the KVO cathode in a K‐ion cell. Synchrotron X‐ray analysis reveals how Sr substitution enhances the electrochemical K‐ion storage properties of the KS3VO cathode. In addition, the KS3VO cathode exhibits superior thermal stability and cycling stability in a full cell coupled with a hard carbon anode compared to the KVO cathode.

Preparation and performance analysis of polyethylene glycol/epoxy resin composite phase change material

It is crucial for their widespread application to develop phase change materials (PCMs) that can be mass-produced and possess high thermal storage capacity and stability. This study uses polyethylene glycol (PEG) as the phase change material and epoxy resin as the matrix to prepare polyethylene glycol/epoxy resin composite phase change materials (EPPCM) by blending and analyzing the effects of PEG's molecular weight and content on EPPCM's performance. The results indicate that PEG and epoxy resin are physically blended without chemical reaction. When the molecular weight of PEG is fixed, the larger the content of PEG, the higher the crystallinity, phase change enthalpy value, and phase change temperature of EPPCM, and the weaker the thermal cyclic stability and mechanical properties. When the content of PEG is fixed, the larger the molecular weight of PEG, the higher the crystallinity, phase change enthalpy value, and phase change temperature of EPPCM, the stronger the thermal cyclic stability, and the weaker the mechanical properties. Using PEG-10000 as the PCM with a PEG to epoxy resin ratio of 1:2.5, the EPPCM shows a phase change exothermic temperature range of 33.4 °C to 45.7 °C, an endothermic temperature range of 54.3 °C to 65.4 °C, a phase change enthalpy of 130.0 J/g, and only 1.56 % mass loss after 30 phase change cycles.

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.

Biomass waste lotus shell-based shape-stabilized phase change composites with improved thermal conductivity for thermal management

Lotus shells represent an underutilized renewable resource with desirable porous architecture for producing bio-based phase change composites (PCMs). This research endeavors to fabricate a series of shape-stable phase change composites (SSPCCs) based on n-docosane (ND) and waste lotus shells to enhance heat utilization, solar photothermal energy conversion, and promote environmental protection. Both carbonization and activation processes play a critical role in the formation of desired pore structures. The carbonized lotus shells (CLS) and activated lotus shells (ALS) exhibit superior specific surface areas, reaching 147.70 m2/g for CLS and 1652.35 m2/g for ALS. Notably, the composite of ND integrated with ALS (ND/ALS) exhibits satisfactory latent heat storage of 93.68 J/g, excellent leakage prevention, and exceptional thermal cycle stability. Subsequently, the ND/ALS displays a significantly enhanced thermal conductivity of 0.482 W/(m·K) with an appreciable increment of 189% compared to ND. Furthermore, the obtained SSPCCs present good chemical compatibility, satisfactory thermochemical stability, and outstanding thermal management capability. In conclusion, the novel waste lotus shell-derived SSPCCs exhibit extensive potential for thermal management, such as heat recovery, solar energy conversion, and temperature regulation. This research not only introduces a promising avenue for enhancing sustainable materials in energy storage and conversion but also pioneers an innovative recycling strategy for waste lotus shells, thereby contributing to both environmental sustainability and efficient resource utilization.

Synergistic enhancement of phase change materials through three-dimensional porous layered covalent triazine framework/expanded graphite composites for solar energy storage and beyond

The challenges of leakage and low thermal conductivity have emerged as obstacles that hinder the advancement of long-term thermal stability and versatility of phase change material (PCM). This study aims to address the challenges of high leakage rate and low thermal conductivity associated with paraffin wax (PW) in phase change energy storage. A composite PCM with a layered microstructure was successfully synthesized by physically blending expanded graphite (EG), covalent triazine framework (CTF), and adsorbed PW. For the first time, the encapsulation of (phase change materials) PCMs using covalent organic frameworks (COF) was realized. Subsequently, various aspects of the prepared materials were thoroughly characterized and analyzed, demonstrating excellent performance. The material exhibited a leakage rate of only 0.18 %, a thermal conductivity approximately 10 times higher than that of pure PW, and a high latent heat of phase change (111.26 J/g). After undergoing 500 thermal cycles of storage and release, the latent heat of phase change remained stable at around 72 %, indicating robust thermal cycle stability. Furthermore, photothermal tests revealed an impressive photothermal conversion efficiency of 86.9 % for the composite PCM, highlighting its remarkable photothermal conversion capability and efficiency. This study provides an innovative solution to the challenges of high leakage rate and low thermal conductivity in paraffin-based phase change energy storage. Additionally, it delivers valuable theoretical guidance and an experimental foundation for the development of more efficient and stablePCMs.

Preparation and Photothermal Properties of Accordion‐Like MXene/Sodium Acetate Trihydrate Composite Phase Change Materials

Phase change materials (PCMs) are promising options for thermal energy storage. Combining sodium acetate trihydrate (SAT) with MXene, the composite phase change materials (CPCMs) have been prepared. The surface morphology, thermal storage performance, and solar energy photothermal conversion efficiency of the CPCMs with various MXene contents are analyzed. According to the microstructure morphology analysis, MXene is accordion‐shaped, and tightly associated with SAT. Differential scanning calorimetry measurement results show that CPCMs possess high latent heat and suitable phase change temperature for the applications of solar heat storage. The absorption wavelength range of SAT/MXene is extended from 200–258 nm to 200–497.7 nm with a photothermal conversion efficiency of 81.3%. SAT/MXene‐2%, SAT/MXene‐8%, and SAT/MXene‐14% have thermal conductivities of 0.84, 1.14, and 1.47 W/ (m · K), respectively, which are higher by 44.9%, 96.6%, and 153.4% than 0.59 W/ (m · K) of pure SAT. CPCMs exhibit excellent thermal stability and reliable cycling stability after 50 cycles, which show that MXene can prevent leakage during the solid‐liquid phase transition process. The expansion of PCM's practical applicability and MXene/SAT composites with good photothermal characteristics create a theoretical foundation for the effective use of renewable energy sources.