Outstanding Thermal Stability Research Articles

Controlling the polymorphs of PVDF membranes: Effects of a salt additive on PVDF polarization during phase separation processes

Polyvinylidene fluoride (PVDF) membranes, acclaimed for their outstanding chemical resistance, thermal stability, and mechanical properties, play a crucial role in diverse industrial purification applications. While various methods have been employed for fabricating PVDF membranes such as thermally induced, evaporation-induced, vapor-induced, and nonsolvent-induced phase separation processes, controlling the polarity of PVDF chains using these techniques remains challenging. Recent studies have shown that the nonpolar α-phase PVDF is susceptible to organic acid fouling owing to hydrophobic interactions, whereas the β-phase PVDF has demonstrated polarity and offers antifouling properties. Herein, porous PVDF membranes predominantly composed of the β-phase were successfully fabricated by incorporating a small amount of LiCl salt into the PVDF dope solution. The addition of LiCl influences ion–dipole moments between ions and PVDF during phase separation, simultaneously affecting the PVDF chain arrangement and membrane morphology. Since the LiCl additive alters both the pore size and structure of PVDF membranes, both freestanding and non-woven supported membranes were prepared and characterized to assess the effects of polarity and pore size on fouling tendency. Characterizations of prepared PVDF membranes revealed considerable changes in the PVDF polymorph, membrane morphology, pore size, and antifouling properties upon introducing the salt additive. Our findings imply that β-phase–dominant PVDF membranes can be effectively utilized in water purification applications.

Preparation of UiO-66 MOF-Bonded Porous-Layer Open-Tubular Columns Using an In Situ Growth Approach for Gas Chromatography.

The thermally stable zirconium-based MOF, UiO-66, was employed for the preparation of bonded porous-layer open-tubular (PLOT) GC columns. The synthesis included the in situ growth of the UiO-66 film on the inner wall of the capillary through a one-step solvothermal procedure. SEM-EDX analysis revealed the formation of a thin, continuous, uniform, and compact layer of UiO-66 polycrystals on the functionalized inner wall of the column. The average polarity (ΔIav = 700) and the McReynolds constants reflected the polar nature of the UiO-66 stationary phase. Several mixtures of small organic compounds and real samples were used to evaluate the separation performance of the fabricated columns. Linear alkanes from n-pentane to n-decane were baseline separated within 1.35 min. Also, a series of six n-alkylbenzenes (C3-C8) were separated within 3 min with a minimum resolution of 3.09, whereas monohalobenzene mixtures were separated at 220 °C within 14s. UiO-66 PLOT columns are ideally suited for the isothermal separation of chlorobenzene structural isomers at 210 °C within 45 s with Rs ≥ 1.37. The prepared column featured outstanding thermal stability (up to 450 °C) without any observed bleeding or significant impact on its performance. This feature enabled the analysis of various petroleum-based samples.

Elaborating NH-Bridged Nitrogen-Rich Energetic Materials via Base-Mediated Dimroth Rearrangement: Synthesis, Characterization, and Performance Study.

The pursuit of heat-resistant energetic materials featuring high thermostability and energy has gained keen interest in recent years owing to their use in coal mining and aerospace domains. In this study, we synthesized 4-((4,6-diamino-1,3,5-triazin-2-yl) amino)-1H-1,2,3-triazole-5-carbonitrile (6) and its perchlorate and nitrate energetic salts (6a and 6b) by incorporating amino bridging (-NH-) using the Dimroth rearrangement (DR) from inexpensive starting materials as a heat-resistant energetic materials. All of the compounds were thoroughly characterized by infrared (IR), NMR, elemental analysis (EA), high-resolution mass spectrometry (HRMS), and thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) studies. Compounds 6a and 6b showed good densities (1.81 and 1.80 g cm-3), detonation performance (VOD = 7505 and 8257 m s-1, DP = 23.47 and 24.41 GPa), insensitivity to mechanical stimuli (IS = 40 J and FS = >360 N), and excellent thermal stability (Td = 307 and 334 °C), surpassing presently used heat-resistant explosive HNS (318 °C). The molecular electrostatic potentials and noncovalent interactions were pursued to understand possible interaction sites and structure-directing interactions in these salts. Their facile synthetic approach, good energetic performance, and outstanding thermal stability indicate that they are the ideal combination for replacing current benchmark heat-resistant explosive HNS. Additionally, this study highlights the use of classical DR for making new energetic materials with fine-tuned properties.

Fabrication and characterization of oxidized starch-xanthan gum composite nanoparticles with efficient emulsifying properties

This study involved the preparation of nanoparticles by combining oxidized starch (OS) with xanthan gum (XG), and emulsions were prepared from this nanoparticle. The physical and chemical characteristics, as well as the emulsification properties of oxidized starch-xanthan gum composite nanoparticles (OGNP), were analyzed. The findings revealed that the OGNP retained spherical shape after the addition of XG, although their diameter increased from approximately 50–150 to 200–400 nm. Zeta potential decreased with XG content. Moreover, emulsions prepared from OGNP exhibited outstanding thermal stability, also showing enhanced storage stability. In addition, emulsions had different rheological properties at different pH values. The apparent viscosity and shear stress of emulsions under alkaline conditions were lower than that of neutral conditions. NaCl increased the apparent viscosity of OGNP-stabilized emulsions while reducing their thermal stability. The nanoparticles prepared in this study have efficient emulsification properties and can extend the application of OS.

Ligand‐Assisted Growth of 2D Perovskite Single Crystal for Highly Sensitive X‐Ray Detectors

AbstractThe emerging 2D layered perovskites have promising optoelectronic properties, good intrinsic stability and reduced ion migration, making them effective for detecting X‐ray radiation. However, their application is constrained by poor out‐of‐plane carrier transport. In this study, inch‐sized high‐quality CsPb2Br5 layered single crystals (SCs) are developed using an organic ligand‐assisted solution process. By modifying the surface energy, the anisotropy of crystal growth is conquered, resulting in CsPb2Br5 SCs with sufficient thickness for X‐ray detection. Importantly, this modification significantly enhanced the crystal quality as the grown CsPb2Br5 SCs exhibited longer photoluminescence lifetime and smaller trap density. Notably, the CsPb2Br5 SCs demonstrate unprecedented out‐of‐plane carrier transport, achieving a high carrier mobility‐lifetime product of 2.53 × 10−2 cm2V−1. This can be attributed to the small interlayer distance and the strong interlayer force of Cs─Br bonding. Furthermore, CsPb2Br5 SCs possess other intriguing attributes for X‐ray detection, including high bulk resistivity and outstanding thermal stability. These advantageous properties enable high‐performance vertical‐structure X‐ray detection with a superior sensitivity of up to 8865.6 µC Gyair−1cm−2 and a low detectable dose rate of 12.7 nGyairs−1. Additionally, CsPb2Br5 SCs exhibit high spatial resolution in X‐ray imaging and exceptional thermal stability, making them promising candidates for nondestructive determination.

Regulating interfacial diffusion of nanocrystal‐in‐glass composites: Insights from atomistic simulation

AbstractBy combining the spectroscopic quality of a crystalline phase with the outstanding thermal and chemical stability of the matrix glass, nanocrystal‐in‐glass composites (NGCs) exhibit excellent optical properties. However, strong interfacial diffusion occurs during high‐temperature encapsulation, leading to the erosion of the nanocrystals and detrimental effects on the final performance. The control of interfacial diffusion has so far relied on intuition and experience, with the underlying physical mechanisms remaining largely unknown. In this study, through atomistic simulations and experimental verification, we have developed atomic models of NGCs, revealing the dynamic characteristics of the interface and elucidating how the glass structure can regulate the interface diffusion. Finally, we demonstrate how a tunable interface can be achieved through compositional adjustments of the glass matrix.

Highly thermally stable SrLaMgTaO6: Cr3+ double-perovskite phosphors for night-vision applications

In this study, a novel thermally stability broad-band near-infrared (NIR) phosphor SrLaMgTaO6 (SLMT): Cr3+ was research, along with investigations into its structure, morphology, PL spectra and crystal field strengths. Additionally, the mechanism of concentration quenching in these samples was investigated, which primarily attributed to electric multipolar interactions notably. Surprisingly, the NIR emission intensity at 423 K remains 80.4 % of its room temperature intensity, which shows its outstanding thermal stability. To comprehend the mechanism behind the exceptional thermal stability of luminescence, a comprehensive analysis in this material was conducted, focusing on factors such as the crystal field strength of the host material and the electron-phonon coupling (EPC) effect. Subsequently, an optimized phosphor coating was applied to a 470 nm LED chip to get a NIR pc-LED device, which was evaluated for its performance. The research demonstrate that SLMT: Cr3+ phosphor is a promising NIR pc-LED.

Boosting Near‐Infrared Emission in Spinel‐Type Phosphor via Oxygen Vacancy Engineering for Versatile Application

AbstractFe3+‐doped MgGa2O4 (MGO: Fe3+) spinel‐type near‐infrared (NIR) phosphor with non‐toxicity, outstanding thermal stability, and tunable emission has recently gained great concern owing to its wide applications. Nevertheless, the existence of detrimental O defects in the MgGa2O4 host and the forbidden d‐d transitions of Fe3+ lead to unsatisfactory luminescence efficiency, limiting the commercial application. In this study, a vacancy repairing engineering has been innovatively developed via F− substitution in MGO: Fe3+ (MGOF: Fe3+) for significantly enhancing NIR emission and maintaining outstanding thermal stability. Specifically, F− substitution with a similar radius effectively repairs the intrinsic O vacancy defects of MGO, thereby prohibiting the detrimental electron‐capturing effect. Meanwhile, F− incorporation can make the lattice of MGO distort and break the forbidden transition of Fe3+. Significantly, the obtained MGOF: Fe3+ presents a 16‐fold higher emission intensity than that of MGO: Fe3+. More important, the MGOF: Fe3+ can remain at 91.17% (363 K) and 85.10% (423 K). Finally, the NIR emission of MGOF: Fe3+ can be used for night vision, non‐destructive biological tissue detection, and food analysis. The proposed vacancy repairing strategy can certainly stimulate some new thoughts and concepts in designing high‐performance phosphors for wider applications.

Boehmite-PVDF-CTFE/F-PI composite separator irradiated by electron beam for high-rate lithium-ion batteries

As an important part of the fields such as renewable energy and electric vehicles, electrochemical energy storage technology faces significant challenges in improving energy density, extending battery life and improving safety. We successfully prepared a composite battery separator of polyvinylidene fluoride-chlorotrifluorinylene (PVDF-CTFE) and fluorinated polyimide (F-PI) -based materials, mixed it with different contents of boehmite nanoparticles, and then modified it by different doses of electron beam irradiation to improve the performance, especially to overcome the problem of maintaining capacity decline in high-speed charging environment. The results showed that the prepared battery separators exhibited outstanding thermal stability, electrochemical properties and ionic conductivity with 12 % boehmite nanoparticles. After 1000 high-speed charge and discharge cycles in current density of 10C, the battery based on the modified separator still maintained a capacity retention rate of 84.4 %, with the initial discharge specific capacity of 111.9 mAhg−1. This means that irradiated separators not only maintain a high energy density in a high-speed charging environment, but also overcome the problem of maintaining capacity decline. Electron beam irradiation further improved the comprehensive performance of the separator. After 1000 and 1500 cycles at the current density of 10C and 15C, the specific discharge capacity of the battery can still retain more than 90 % and 80 % of the initial specific discharge capacity, which provides a longer life in practical applications.

Outstanding shape memory effect and thermal stability of Cu–Al–Ni-based high temperature shape memory alloys achieved by Gd and Mn doping

In this paper, the effects of Mn element and rare earth element Gd on the microstructure, thermal stability, mechanical properties and shape memory effect of polycrystalline Cu-12.0Al-4.0Ni and Cu-12.0Al-4.0Ni-1.5Mn-xGd high-temperature shape memory alloy were investigated. The results show that the Cu-12.0Al-4.0Ni alloy exhibits millimeter-sized grain, dual-phase structure with coexistence of 18R and 2H martensite and poor thermal stability. When the Mn and Gd element was added to Cu-12.0Al-4.0Ni alloys, the grain size can be refined by an order of magnitude, and the 2H martensite disappeared completely, accompanied by the formation of the AlCu4Gd phase, meanwhile, thermal stability is significantly improved. The grain refinement improves the mechanical properties and shape memory effect of Cu-12.0Al-4.0Ni-1.5Mn-xGd alloys. When x = 0.3, the compressive fracture stress, compressive fracture strain and recoverable strain can reach 969 MPa, 15 % and 8 %, respectively.

Controlling Fluorination Density of Soluble Polyimide Gate Dielectrics and its Influence on Organic Crystal Growth and Device Operational Stability.

Fluorinated polyimides (PIs) are among the most promising candidates for gate dielectric materials in organic electronic devices because of their solution processability and outstanding chemical, mechanical, and thermal stabilities. Additionally, fluorine (F) substitution improves the electrical properties of PI thin films, such as enhanced dielectric properties and reduced surface trap densities. However, the relationship between the fluorination density of PIs and crystal growth modes of vacuum-deposited conjugated molecules on PI thin films, which is directly related to the lateral charge transport along the PI-organic semiconductor interface, has not been systematically studied. Herein, five different soluble PIs with different F densities were synthesized, and the correlation between fluorination and thin-film properties was systematically investigated. Not only were their dielectric properties modulated, but the growth modes of the organic molecules deposited on the PI thin films also changed with increasing surface F density. This phenomenon was observed by both surface and crystallographic analyses, which resulted in extremely high operational stability of field-effect transistors and the successful fabrication of organic complementary circuits. We believe that the correlation between PI backbone fluorination and its thin-film properties will provide practical insights into the material design based on controlled molecular directed surface assembly on fluorinated polymer dielectrics.

Fabrication of high-flux PTFE hollow fiber membranes through nonionic surfactant infiltration coupled with mussel-inspired chemistry coating

Polytetrafluoroethylene (PTFE) hollow fiber membrane holds tremendous potential for the treatment of complex wastewater due to its outstanding chemical and thermal stability. However, its treatment efficiency is often hindered by the low water permeate flux arising from the inherent hydrophobicity of PTFE. Here, we present a gentle and convenient hydrophilic modification method that involves immersion in a nonionic surfactant aqueous solution, followed by dopamine self-polymerization. The nonionic surfactant facilitated the penetration of the dopamine solution into the membrane, where dopamine self-polymerized to form a hydrophilic layer on the surface and inner pores of the membrane. The hydrophilicity-modified PTFE hollow fiber membranes demonstrated an impressive increase in water permeate flux, reaching 10231.4 L m−2 h−1, nearly ten times that of the original membrane. Even after prolonged exposure to a strong acid solution (pH = 1) or an oxidant solution (1000 mg L−1 NaClO) for two weeks, this membrane still maintained its favorable water permeability. Furthermore, the modified PTFE membranes also exhibited remarkable resistance to fouling by humic acid. These results showcased a straightforward method for designing a hydrophilic layer on PTFE hollow fiber membranes, underscoring their significant potential for real wastewater treatment applications.

Synthesis and application of environmental plasticizers based on benzene polyacid ester

AbstractUsing benzene‐1,3,5‐tricarboxylic acid, trimellitic anhydride, 2‐propylheptanol and 2‐ethylhexanol as raw materials, four kinds of environmental plasticizers were prepared, which were used as additives for polyvinyl chloride (PVC) products. Compared with commercially available di (2‐ethylhexyl) phthalate (DOP), di (2‐ethylhexyl) terephthalate (DOTP), and tributyl citrate (TBC), the application performance and plasticizing performance were compared. The structure of the target product was analyzed by fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy to verify the fingerprint region of the molecular structure of the product. The properties of plasticized PVC films were tested by thermal weight loss analysis, oven thermal aging test, migration and volatility resistance test, DMA analysis, and scanning electron microscopy. The plasticizing mechanism was confirmed through quantum chemical calculations, and the results of the calculations were in line with the migration outcomes. The results showed that compared with commercially available plasticizers, benzene polyacid ester plasticizers had better thermal stability, and better cold resistance in the polar environments, suitable for high‐temperature and water‐based environments.Highlights The four plasticizers prepared in this study were compared with reference plasticizers, and the plasticizing mechanism was validated through quantum chemical calculations. The PVC film plasticized with benzene polyacid ester prepared in this study demonstrates outstanding thermal stability, surpassing certain plasticizers reported in current literature. Benzene polyacid esters plasticized PVC film has migration stability under various conditions, it has great potential in packaging and other applications.

Preparation of a bio-based PU/EP IPN concrete adhesive with optimized performance and decent adhesion

An adhesive serves as a vital tool in construction, repair, and rehabilitation projects. Typically crafted from polymer materials such as epoxies or polyurethane latex, it facilitates the creation of resilient bonds between a variety of surfaces, ranging from concrete-concrete and metal-concrete to concrete-composites. However, employing epoxy or polyurethane individually as adhesives often demonstrate insufficient performance and weak interfacial adhesion during service. In this study, an adhesive combining polyurethane and epoxy was synthesized, featuring an interpenetrating polymer network (IPN) structure. This innovative agent was created using polyols sourced from soybean oil and a commercial epoxy resin. By tuning the infusion of polyurethane content, the resultant resin exhibited favorable flowability in civil applications, simultaneously improved strength and toughness due to the IPN structure, and outstanding thermal stability. Notably, the incorporation of 20 wt% polyurethane yielded a polymer with a remarkable tensile strength of 35.9 MPa. Additionally, the bonding adhesion of the prepared resins on concrete specimens was investigated through splitting tensile test and shear strength test. The study explored the influences of polyurethane content, concrete strength, and adhesive layer thickness on interfacial bonding strength. The introduction of an IPN structure within the PU-20 agent proved advantageous for enhancing the bonding adhesion of the concrete, resulting in remarkable interfacial tensile and shear strengths of 4.56 MPa and 21.73 MPa, respectively.

Generation of protective ceramic coatings on magnesium by laser treatment of Al2O3/ZrO2 filled organosilazane

Protective ceramic coatings are frequently the most common solutions for problems like corrosion and wear. Polymer derived ceramics technology is suitable for the preparation of ceramic coatings by pyrolysis in a furnace but requires high temperatures for the ceramization. To overcome this restriction a Nd:YVO4 laser (λ = 1064 nm) as energy source was used to process a novel ceramic coating system composed of an organosilazane with zirconia and alumina particles specially to protect magnesium. The resulting dense ceramic coating with a thickness up to 20 µm exhibits very good adhesion (25.9 ± 2.7 MPa) to the magnesium substrate, exceptionally high hardness (19.79 ± 1.90 GPa), an outstanding thermal shock stability but also a low coefficient of friction (0.21 ± 0.02) and a very good wear protection towards a SiC counter body. Furthermore, the coating protects the magnesium substrate effectively against corrosion (5 wt% aqueous NaCl solution).

Synthesis of ZnO nanorods decorating with Ag nanoparticles on flexible polyimide substrate for visible photodetector application

Polyimide (PI), which have many remarkable features such as excellent mechanical strength, outstanding thermal stability, exceptional electric properties, etc, is a potential carrier for optoelectronic devices due to its abundant applications. However, because of chemical inertness and smooth surface that led to the growth of materials on this substrate being more complex than that on rigid substrate, thus, this report aims to emphasise the synthesis of ZnO NRs decorated with the Ag NPs on flexible substrate for photodetector application. In this study, we successfully synthesise ZnO NRs/Ag NPs on a flexible PI substrate by the hydrothermal method. The performance of our photodetector in visible region (395 nm) exhibits via the responsivity of the device, which recorded value of ca. 40.16 mA W−1 at 1.66 mW cm−2. With obtained results, our research can pave the way for future studies based on flexible optoelectronic devices.

Sustainable production of biodiesel enabled by acid-base bifunctional ZnF2 via one-pot transformation of Koelreuteria integrifoliola oil: Process optimization, kinetics study and cost analysis

Against the backdrop of energy crisis and quest for carbon neutrality, efficient utilization of heterogeneous catalysts to facilitate one-pot conversion of low-quality nonedible oils into biodiesel, shows enormous promise for the reduction of carbon footprints and environmental pollution. In this study, an effective heterogeneous catalyst, acid-base bifunctional mesoporous ZnF2 (MP-ZnF2) was successfully fabricated for biodiesel synthesis from Koelreuteria integrifoliola oil (KIO, acid values of 8.26 mg KOH/g) via facile one-pot process. Meanwhile, systematic characterization showed the large specific surface area (62.9 m2/g), abundant mesoporous (12.15 nm), outstanding thermal stability, and plentiful stable acid-base sites (1.22 and 0.56 mmol/g) of MP-ZnF2. Consequently, MP-ZnF2 achieved a high biodiesel yield of 97.15% under moderate conditions (103 °C, 6.2 h, 10.2 wt% catalyst dosages, 29:1 MeOH/KIO molar ratio) optimized by response surface methodology (RSM). More importantly, through the kinetic investigation, a low activation energy of 49.24 kJ/mol explained the reason for its high activity, and the possible reaction mechanism of (trans)esterification was also proposed. In addition, MP-ZnF2 demonstrated satisfactory reusability (6th cycle, >90%), water resistance (8 wt% water content, 89.25%), and versatility (all yields >90%). According to cost analysis, the price of biodiesel in this work was about 0.64 $/kg. Notably, the as-prepared biodiesel conformed to ASTM D6751 and EN 14,214 standards, indicating great application prospects. It was demonstrated that one-pot transformation of KIO into biodiesel using acid-base bifunctional MP-ZnF2 contributes to the sustainable development of clean energy.

Highly thermally conductive composite films by the rational assembly of aramid nanofibers with low-dimensional nanofillers

Highly efficient thermal management of electronic devices has grown in significance with the burgeoning of semiconductor technology and 5th generation communication. It is urgently desired to rationally construct highly thermally conductive composite films for enhancing the performance, service life and operation reliability of electronic equipment. Aramid nanofibers (ANFs), as one of the most promising building blocks to fabricate high-performance and multifunctional composite films, have attracted wide attention of researchers over the past few years due to its impressive mechanical performances, excellent electric insulation, and outstanding thermal stability. Especially, the rational assembly of ANFs with low-dimensional thermally conductive nanofillers exhibits significant opportunity for developing highly thermally conductive flexible composite films. However, there is no specialized review to systematically summarize the research advances and prospective challenges of this area until now. Herein, the preparation strategies, structure and properties, as well as the potential applications of various ANFs-based thermally conductive composite films with different low-dimensional nanofillers are highlighted. Finally, possible challenges and opportunities for ANFs-based thermally conductive composite films are envisioned. This brief review delivers the readers an in-depth understanding of the thermal conduction performances of ANFs-based composite films, which may give meaningful enlightenment for designing advanced thermal management materials and ANFs-based functional composites.

A wide-angle broadband dual-polarization electromagnetic absorbing structure based on the carbonyl iron powder/polydimethylsiloxane composites

Electromagnetic absorbing structure with wide-angle and broadband absorption plays a vital role in radar stealth. Hence, a novel gradient composite multilayer absorbing structure (GCMAS) is designed and fabricated by a simple and low-cost direct ink writing (DIW) 3D printing technology. The GCMAS consists of the CIP/PDMS composites composed of carbonyl iron powder (CIP) and polydimethylsiloxane (PDMS), which have outstanding flexibility, chemical and thermal stability. By metastructure design of gradient composites, a material-structure–function integrated absorbing structure with 50 wt% CIP/PDMS in the top layer, 60 wt% CIP/PDMS in the middle two layers, and 70 wt% CIP/PDMS in the bottom two layers is obtained. Simulations demonstrate that the designed GCMAS with the thickness of 13 mm can achieve the −10 dB absorbing bandwidth in the frequency range from 2.88 to 38.24 GHz, and the absorbing bandwidth corresponding to −15 dB in 2.97–36.17 GHz. The maximum reflection loss is −42.17 dB at 22.96 GHz. Experiments demonstrate that the GCMAS can achieve the −10 dB absorbing bandwidth in 3.6–40 GHz. Moreover, the GCMAS also can maintain the broadband and strong absorbing performance with incident angle from 0° to 50° for transverse electric (TE) polarization and 0° to 60° for transverse magnetic (TM) polarization. This work provides a promising strategy for the fabrication of functional gradient composites and flexible or bendable absorbing structure, which have great potential in satellite communications and radar stealth.

New frontiers in thermal energy storage: An experimental analysis of thermophysical properties and thermal stability of a novel ternary chloride molten salt

It has been always a daunting task to develop thermal systems with a wide range of thermochemical properties and high stability. It presents a significant challenge, especially when aiming to utilize them for heat storage and transfer applications. In this regard, the thermal characteristics and thermal stability behaviour of molten salt mixture as a heat transfer fluid (HTF) at high temperatures were explored. A novel ternary eutectic salt mixture (base mixture) made of cuprous chloride (CuCl), potassium chloride (KCl) and sodium chloride (NaCl) was investigated as HTF for thermal energy storage (TES) system with a range up to 653 °C in a concentrated solar power (CSP) plant. To extend the temperature span and stability, the effect of an additive was investigated. Different compositions were studied in detail concerning the properties and stability regarding the additive. The molten salt with 7 % CaCl2 additive improved thermal stability and operating temperature from 653 °C to 700 °C. The transport characteristics and thermal stability of the eutectic mixture with and without the additive were measured by high-temperature thermal analyzers. The results indicated that the melting temperature decreased and the average specific heat capacity considerably increased with the addition of CaCl2 additive compared to the ternary chloride base mixture. As the temperature increased, the eutectic salt mixture exhibited a reduction in viscosity and density. The viscosity and density of the salt mixture with and without the additive were almost uniform at 700 °C. The average thermal conductivity of the ternary salt mixture with and without additives was 0.72 W/(m°C) which is much more than that of Solar and Hitec salts. In a 100 h experiment of long-period isothermal stability, the eutectic salt mixture showed less than 4 % weight loss at 700 °C. It was defined as the highest operating temperature at which the eutectic salt mixture remained stable. The stability and recyclability of the salt mixture were confirmed through the short-period stability test. The effect of the CaCl2 additive on thermal stability of base salt mixture was analyzed by X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) techniques. According to the results, this novel eutectic salt mixture had outstanding thermal stability up to 700 °C and could be employed as a viable TES material in CSP plants.