Operating Temperature Range Research Articles

Excellent Thermoelectric Performance Realized in Copper Sulfide Magnetic Nanocomposites Via Modified Solid States Reaction.

Solid-state reactions, which are the basic reactions involved in the preparation, processing, and application of materials, are ubiquitous in material science and chemistry research. In the fields of metallurgy and geology, a significant number of complex chemical reactions occur during the smelting of ores. Inspired by the smelting of copper concentrate, this work applies modified metallurgical chemical reactions to the field of (thermoeletric) TE materials. By controlling the reaction temperature and composition, porous copper sulfide magnetic nanocomposites can be formed. Regulating the composition generates numerous precipitates and Cu-rich phases, and controlling the microstructure facilitates the formation of porous structures. The second phase and porous structure effectively decreased thermal conductivity. Furthermore, the introduction of ferromagnetic Fe3O4 particles plays a role in reducing carrier concentration and forming potential barrier scattering low energy carriers, which improves the Seebeck coefficient of the samples. Ultimately, the optimum figure of merit (ZT) of ≈1.3 at 773 K for the Cu1.8S + 2 wt.% Fe3O4 bulk sample and an average ZT of 0.57 over the entire operating temperature range. The modified solid states reaction between oxides and sulfides could be employed to optimize electrical and thermal transport properties for sulfide TE material, as well as sulfide batteries, sulfide photoelectric materials, and sulfide catalytic materials.

Designing a Lithium-Ion Cell for Studies of a Single Degradation Mechanism Over a Wide Temperature Range

Abstract 18650-sized cylindrical cells containing single crystal Li[Ni0.6Mn0.4Co0.0]O2, Li[Ni0.6Mn0.35Co0.05]O2, and Li[Ni0.6Mn0.3Co0.1]O2 positive electrodes along with artificial graphite negative electrodes were constructed to be balanced at 4.05 V. These cells were designed so that they would have only the single degradation mode of lithium inventory loss due to the solid-electrolyte interphase layer growth. Cells were cycled both at C/3 and C/20 over a wide temperature range from 20 to 100°C in order to accelerate degradation processes at higher temperatures and more rapidly predict low-temperature behaviour. A low upper cutoff voltage of 4.0 V was selected to avoid electrolyte oxidation, and an electrolyte composition incorporating pure lithium bis(fluorosulfonyl)imide salt was chosen based on the temperature and voltage range of operation. A thorough post-cycling analysis was performed to verify the elimination of all degradation modes except inventory loss and minor impedance growth, which enabled the application of a simple square root time model to make accurate lifetime predictions. In addition, the capacity retention of these cells at elevated temperature is incredible, with the best cells retaining 87% capacity after 1400 C/3 cycles (one year) continuously at 85°C.

Synthesis of Polyether Ester Plasticizer and Its Application Performance in Hydrogenated Nitrile Butadiene Rubber

ABSTRACTFour polyether ester plasticizers containing both ester groups and ether bonds were synthesized using 1,4‐butanediol, adipic acid, and alkyl ether alcohols as raw materials. By varying the type of end‐capping alcohol ether, the following plasticizers were prepared: poly (butylene adipate dibutyl ether) (PBADBE), poly (butylene adipate butyl ether) (PBABE), poly (butylene adipate dimethyl ether) (PBADME), and poly (butylene adipate methyl ether) (PBAME). These plasticizers were characterized by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance spectroscopy (1H‐NMR), and thermogravimetric (TG) analysis. Furthermore, their differences in cold resistance, heat resistance, and physical‐mechanical properties in hydrogenated nitrile‐butadiene rubber (HNBR) were investigated. The results showed that among the rubber compounds containing the four polyether‐ester plasticizers, the compound with PBADME demonstrated superior heat resistance and low‐temperature performance. Specifically, the PBADME‐containing compound exhibited a TR10 temperature of −39.9°C and a brittleness temperature of −54°C. This significantly broadened the operating temperature range of the plasticizer, making it suitable for applications requiring both high‐temperature and low‐temperature performance.

Wide-temperature and high-voltage Li||LiCoO2 cells enabled by a nonflammable partially-fluorinated electrolyte with fine-tuning solvation structure

Efficient, safe, and reliable energy output from high-energy-density lithium metal batteries (LMBs) at all climates is crucial for portable electronic devices operating in complex environments. The performance of corresponding cathodes and lithium (Li) metal anodes, however, faces significant challenges under such demanding conditions. Herein, a nonflammable electrolyte for high-voltage Li||LCO cells has been designed, including partially-fluorinated ethyl 4,4,4-trifluorobutyrate (ETFB) as the key solvent, guided by theoretical calculations. With this ETFB-based electrolyte, Li||LCO cells exhibit enhanced reversible capacities and superior capacity retention at an elevated charge voltage of 4.5 V and a wide operating temperature range spanning from −60 °C to 70 °C. The cells achieve 67.1% discharge capacity at −60 °C, relative to room temperature capacity, and 85.9% 100th-cycle retention at 70 °C. The outstanding properties are attributed to the LiF-rich interphases formed in the ETFB-based electrolyte with a fine-tuned solvation structure, in which the coordination environment in the vicinity of Li+ cations and the distance between anion and solvents are subtly adjusted by introducing ETFB. This solvation structure has been mutually elucidated through joint spectra characterizations and atomistic simulations. This work presents a new strategy for the design of electrolytes to achieve all-climate reliable and safe application of LMBs.

A field study on thermal comfort and adaptive behaviour of university open-plan offices in severe cold regions of China

ABSTRACT This study investigates the thermal comfort and adaptive behaviours of occupants in open-plan office spaces at a university located in Northeast China, a region characterized by severely cold winters with an average temperature ≤−10°C in the coldest month. The research focuses on the interaction between buildings and occupants from an indoor environmental quality perspective, contributing to the field of occupant-centric building design and operation by studying thermal comfort, adaptive behaviour, and energy-efficient heating strategies in severe cold regions. By employing field measurements and a subjective questionnaire survey, we summarized the environmental factors contributing to thermal discomfort and their respective weights. The results reveal that air temperature, radiant asymmetry caused by envelopes, and relative humidity are the three most significant factors, with weights of 0.376, 0.209, and 0.194, respectively. Furthermore, a fuzzy comprehensive evaluation method was employed to determine the thermal neutral operating temperature (22.5°C) and the acceptable operating temperature range (19.5°C to 25.5°C). Based on the analysis of occupant behaviour characteristics and preferences, a suitable winter heating setting is proposed for open-plan university offices. These findings support the development of more accurate building performance simulations and inform strategies for low-energy building management in severe cold regions.

Preparation, Properties and Application of Ionic Liquid Gels

Ionic liquid (IL) gels, have garnered significant attention in recent years on account of their distinctive amalgamation of properties, encompassing ionic conductivity, environmental stability, and flexibility. In this paper, the function of ILs in regulating gel structural was reviewed, with an emphasis placed on the preparation and properties of IL gels. Additionally, we probed into the superiority of IL gels over conventional hydrogels, such as enhanced mechanical strength, thermal stability, and a broader range of stable operating temperatures. The potential applications of IL gels in the domains of energy storage, separation and catalysis, environmental protection, and biomedicine were deliberated. Finally, we undertake a series of summaries and prospects for IL gels, with the aim of opening up novel perspectives and attracting more attention for the practical application of IL gels.

Numerical Analysis of Temperature Distribution During Charging Process of Vertically Installed Hydrogen Tanks

Recent advancements in hydrogen tank technology have favored the use of composites over metals for weight reduction, although at the cost of a narrower operating temperature range. Therefore, this study aims to establish safety standards for charging tube skids—large tanks positioned vertically within hydrogen transport vehicles—by examining the variations in temperature distribution under different charging environments through numerical analysis. A two-dimensional axisymmetric model was developed based on ANSYS Fluent to incorporate the effect of buoyancy by applying gravitational conditions along the axial direction. The study analyzed the impact of various charging and environmental conditions (charging time (0~240 min), inlet temperature, ambient temperature, initial temperature (−20 °C~40 °C), and initial pressure (5~20 bar)) on temperature distribution, ultimately deriving a regression equation to predict the tank’s maximum temperature. The findings indicate that the initial temperature has the most significant correlation with the tank’s temperature, followed by charging time and ambient temperature. Inlet temperature and initial pressure demonstrated minimal influence within the study’s scope. The derivation of predictive formulas for the maximum temperatures of the tank’s three regions, all showing an R2 value of 0.99 or higher, highlights the practicality of these results. This study’s insights are expected to contribute to further research aimed at optimizing charging conditions for tube skids and other hydrogen tanks.

High Entropy: A General Strategy for Broadening the Operating Temperature of Magnetic Refrigeration.

Lattice distortion and disorder in the chemical environment of magnetic atoms within high-entropy compounds present intriguing issues in the modulation of magnetic functional compounds. However, the complexity inherent in high-entropy disordered systems has resulted in a relative scarcity of comprehensive investigations exploring the magnetic functional mechanisms of these alloys. Herein, we investigate the magnetocaloric effect (MCE) of the high-entropy intermetallic compound Gd0.2Tb0.2Dy0.2Ho0.2Er0.2Co2. Notably, the operating temperature range of the MCE broadens by an order of magnitude from 9 to 83 K while maintaining the refrigeration capacity compared to ErCo2. Atomic-scale microstructure analysis and atomic pair distribution function measurements reveal that lattice distortion stabilizes the cubic structure and induces disorder in the chemical environment of magnetic atoms. First-principles calculations point out that the enhanced average correlation energy raises the Curie temperature. The random distribution of elements across these sites induces local magnetic disorder around magnetic atoms with lower correlation energy, broadening the operating temperature range of MCE. This study not only significantly advances the understanding of the magnetic behavior of high-entropy alloys but also promotes the research progress of high-entropy functional compounds.

Computational Fluid Dynamic Modeling of Pack-Level Battery Thermal Management Systems in Electric Vehicles

In electric vehicles (EVs), the batteries are arranged in the battery pack (BP), which has a small layout space and difficulty in dissipating heat. Therefore, in EVs, the battery thermal management systems (BTMSs) are critical to managing heat to ensure safety and performance, particularly under higher operating temperatures and longer discharge conditions. To solve this problem, in this article, the thermal analysis models of a 3-battery-cell BP were created, including scenarios (1) natural air cooling without a BTMS; (2) natural air cooling with water cooling hybrid BTMS; and (3) forced air cooling plus water cooling composite BTMS. The thermal performances of the pack-level BPs were simulated and analyzed based on computational fluid dynamics (CFD). A variety of boundary conditions and working parameters, such as ambient temperature, inlet coolant flow rate and initial temperature, discharge rate, air flow rate, and initial temperature, were considered. The results show that without a BTMS (Scenario 1), the maximum temperature in the BP rises rapidly and continuously to reach 63.8 °C, much higher than the upper bound of the recommended operating temperature range (ROTR between +20 °C to +35 °C) under the extreme discharge rate of 3 C and even if the discharge rate is 2 C. With a hybrid BTMS (Scenario 2), the maximum temperature in BP rises to about 38.7 °C, slightly above the upper bound of the ROTR. Lowering the coolant (water) initial temperature can effectively lower the temperature up to 5.7 °C in BP, but the water flow rate cannot since the turbulence model. While with a composite BTMS (Scenario 3), the temperature can be further lowered up to 1.5 °C under the extreme discharge rate of 3C, just reaching the upper bound of the ROTR. In addition, lowering the initial coolant temperature or air temperature can effectively decrease the temperatures up to 5.1 and 1.0 °C, respectively, in BP, but the coolant flow rate (due to the turbulence model) and the air flow rate cannot. Finally, the thermal performances of the different battery cells in the BP with different cooling systems and at the different positions of the BP were compared and analyzed. The present work may contribute to the design of BTMSs in the EV industry.

Elemental Segregation and Solute Effects on Mechanical Properties and Processing of Vanadium Alloys: A Review

Vanadium (V) alloys, such as V-Cr, V-Ti, and V-Cr-Ti alloys, are promising candidates for structural components in fusion energy systems because of their low activation, excellent radiation resistance, good compatibility with liquid lithium, and high ductility. Despite these advantages, the limited high-temperature strength and poor creep performances of V alloys have constrained their operating temperature range, challenging the application of these materials over the past few decades. The mechanical behavior is strongly dependent on microstructural features, including precipitates, intergranular and intragranular boundaries, dislocations, and point defects. At the same time, these features serve as preferable sites for solute or impurity atoms to segregate. The elemental segregation alters the local chemistry and stability of these defects, influencing microstructural evolutions and various materials properties that are essential for fusion energy applications. This review paper aims to provide a comprehensive overview of experimental and computational studies on elemental segregation and solute/impurity effects on the mechanical behaviors and microstructural evolution in V alloys. The conventional and advanced manufacturing processes of V alloys will be also discussed. Finally, this review will provide a concise perspective on the potential research directions of V alloys for future fusion reaction applications.

Rational Design of Prussian Blue Analogues for Ultralong and Wide-Temperature-Range Sodium-Ion Batteries.

Architecting Prussian blue analogue (PBA) cathodes with optimized synergistic bimetallic reaction centers is a paradigmatic strategy for devising high-energy sodium-ion batteries (SIBs); however, these cathodes usually suffer from fast capacity fading and sluggish reaction kinetics. To alleviate the above problems, herein, a series of early transition metal (ETM)-late transition metal (LTM)-based PBA (Fe-VO, Fe-TiO, Fe-ZrO, Co-VO, and Fe-Co-VO) cathode materials have been conveniently fabricated via an "acid-assisted synthesis" strategy. As a paradigm, the FeVO-PBA (FV) delivers a superb rate capability (148.9 and 56.1 mAh/g under 0.5 and 100 C, respectively), remarkable cycling stability over 30,000 cycles, high energy density (259.7 Wh/kg for the full cell), and a wide operation-temperature range (-60-80 °C). In situ/ex situ techniques and density functional theory calculations reveal the quasi-zero-strain and multielectron redox mechanisms of the FeVO-PBA cathode during cycling, supporting its higher specific capacity and stable cycling. It is considered that the d-d electron compensation effect between Fe and V enhanced the reversibility and kinetics of redox reactions and simultaneously improved the electronic conductivity and structural stability of the FeVO-PBA cathode. This work may pave a new way for the rational design of high-performance cathode materials with bimetallic reaction centers for SIBs.

Effect of Macrocapsule Geometry on PCM Performance for Thermal Regulation in Buildings

The integration of phase-change materials (PCMs) into thermal energy storage systems offers significant potential for reducing energy consumption and improving thermal comfort, crucial issues for achieving sustainable building stocks. Nevertheless, the performance of PCM-based systems is strongly influenced by the container geometry. Among the various forms of incorporating PCMs into building applications, macroencapsulation is the most versatile and is, therefore, widely used. Herewith, this paper analyzes the impact of macrocapsule geometry on PCM thermal performance. Thermal properties of the material were first tested using Differential Scanning Calorimetry at five heating/cooling rates to evaluate its influence on phase-change temperatures and enthalpy. Then, an experimental setup evaluated four macrocapsule geometries on the enclosed PCM behavior during charging and discharging processes. The PCM characterization revealed that the slowest-tested rate minimized the supercooling effect. Analysis across different macrocapsule geometries showed that sectioning the contact surface improved heat transfer efficiency by fully mobilizing the PCM and reducing phase-change times. Conversely, double-layered geometry designs hindered heat transfer, presenting challenges in completing PCM charging and discharging. These findings suggest that optimizing its performance is a necessary direction for further research, which may include adjusting the PCM operating temperature range across layers or redesigning the geometry to misalign contact surfaces.

Defect Chemistry Engineering to Regulate the Excellent ZTave Value of Nonstoichiometric Ca3-xCo4O9 (0 ≤ x ≤ 0.06) Ceramics.

Cobalt-based oxides have attracted significant attention as p-type thermoelectric materials due to their wide operational temperature range. However, their low average figure of merit (ZTave) value has hindered service performance. A series of cation vacancies as Ca-active sites were introduced into Ca3-xCo4O9 (0 ≤ x ≤ 0.06) by defect chemistry engineering to regulate the excellent ZTave value. The Ca-active sites of Ca3-xCo4O9 ceramics induced lattice distortion and point defects, which were unequivocally confirmed by the iDPC-STEM results. The power factor from 0.18 mW/(m·K2) to 0.38 mW/(m·K2) and the electrical conductivity from 54.8 to 108.3 S/cm were achieved for the Ca2.96Co4O9 sample. A notable ZT value of 0.32 was obtained at 1073 K. Furthermore, the high ZTave of approximately 0.166 reached within the temperature range of 323-1073 K, representing a 3.25 times improvement compared to pure Ca3Co4O9 ceramics. This study highlights defect chemistry engineering as an effective strategy for optimizing the thermoelectric performance of nonstoichiometric Ca3Co4O9 ceramics, offering promising prospects for the development of Ca3Co4O9-based thermoelectric materials.

Electrolyte chemistry towards ultra‐high voltage (4.7 V) and ultra‐wide temperature (−30 to 70 °C) LiCoO2 batteries

LiCoO2 batteries for 3C electronics demand high charging voltage and wide operating temperature range, which are virtually impossible for existing electrolytes due to aggravated interfacial parasitic reactions and sluggish kinetics. Herein, we report an electrolyte design strategy based on a partially fluorinated ester solvent (i.e., DFEA) that achieves a balance between weak Li+–solvent interactions, sufficient salt dissociation, high interfacial stability, and superior thermal stability to address the aforementioned challenges. The resulting high‐voltage wide‐temperature electrolyte (HWE) not only possesses low desolvation energy, fast Li+ transport, high oxidation stability, excellent thermal‐abuse tolerance and non‐flammability, but also enables the formation of both inorganic‐rich cathode electrolyte interphase (CEI) and solid electrolyte interphase (SEI). Owing to the above merits, this HWE endows the highly stable operation of LiCoO2 cathodes under an ultra‐high voltage of 4.7 V and Graphite||LiCoO2 batteries in an ultra‐wide temperature range of −30 to 70 °C. Meanwhile, a 1.7 Ah‐level 4.6 V Graphite||LiCoO2 pouch cell with a high energy density of 240 Wh kg−1 also delivers excellent cycling stability, representing a significant advancement in the design of electrolytes towards ultra‐high voltage and ultra‐wide temperature batteries.

Topological Magnetic Textures Mediated Magnetocaloric Effect in Janus Monolayer

AbstractTopological magnetic textures (TMTs) such as skyrmions, merons, and vortices are promising for next‐generation spintronic technology. Here, the prospect of TMTs in cooling technology is explored, and the influence of TMTs on magnetocaloric effect (MCE) in typical Janus monolayers (symmetry‐broken VSi2N4 derivatives) that exhibit prominent Dzyaloshinskii–Moriya interaction (DMI) is specifically elaborated. It is found that the Janus monolayers VSi2N2P2, VSi2N2As2 and VSi2NAs3 allow for versatile TMTs including bimerons, meron pairs and skyrmions. Skyrmions and bimerons are demonstrated to remain stable up to 100 K. Under external magnetic fields, TMTs either experience shrinkage or exhibit a significant magnetization reversal. This results in TMTs‐mediated MCE driven by topological magnetic‐to‐ferromagnetic phase transition, which intrinsically differs from the conventional MCE driven by paramagnetic‐to‐ferromagnetic phase transition. The TMTs‐mediated MCE is revealed to benefit from a combination of pseudo‐first‐order and second‐order phase transition and thus exhibit a broader operating temperature range. These findings offer an in‐depth understanding on the role of TMTs in MCE of Janus monolayers and can inspire nanoscale 2D cooling science and technology.

Electrolyte Chemistry Towards Ultra-High Voltage (4.7 V) And Ultra-Wide Temperature (-30 to 70 °C) LiCoO2 Batteries.

LiCoO2 batteries for 3 C electronics demand high charging voltage and wide operating temperature range, which are virtually impossible for existing electrolytes due to aggravated interfacial parasitic reactions and sluggish kinetics. Herein, we report an electrolyte design strategy based on a partially fluorinated ester solvent (i.e., DFEA) that achieves a balance between weak Li+-solvent interactions, sufficient salt dissociation, high interfacial stability, and superior thermal stability to address the aforementioned challenges. The resulting high-voltage wide-temperature electrolyte (HWE) not only possesses low desolvation energy, fast Li+ transport, high oxidation stability, excellent thermal-abuse tolerance and non-flammability, but also enables the formation of both inorganic-rich cathode electrolyte interphase (CEI) and solid electrolyte interphase (SEI). Owing to the above merits, this HWE endows the highly stable operation of LiCoO2 cathodes under an ultra-high voltage of 4.7 V and Graphite || LiCoO2 batteries in an ultra-wide temperature range of -30 to 70 °C. Meanwhile, a 1.7 Ah-level 4.6 V Graphite || LiCoO2 pouch cell with a high energy density of 240 Wh kg-1 also delivers excellent cycling stability, representing a significant advancement in the design of electrolytes towards ultra-high voltage and ultra-wide temperature batteries.

High performance eutectogel-based thermocell with a wide operating temperature range through a water-containing deep eutectic solvent strategy

High performance eutectogel-based thermocell with a wide operating temperature range through a water-containing deep eutectic solvent strategy

Sensing of n-butanol vapours using an oxygen vacancy-enriched Zn2SnO4-SnO2 hybrid-composite.

The precise identification of various toxic gases is important to prevent health and environmental hazards using cost-effective, efficient, metal oxide-based chemiresistive sensing methods. This study explores the sensing properties of a chemiresistive sensor based on a Zn2SnO4-SnO2 microcomposite for detecting n-butanol vapours. The microcomposite, enriched with oxygen vacancies, was thoroughly characterized, confirming its structure, crystallinity, morphology and elemental composition. The sensor demonstrated high repeatability across a temperature range of 275-350 °C and concentrations from 100 to 1000 ppm, with the highest response observed at 350 °C. The concentration-dependent response of the sensor towards n-butanol follows a linear relationship within the studied operating temperature range. The response time increases as the concentration of n-butanol increases. Conductance transients were modelled using the Langmuir-Hinshelwood mechanism, showing temperature-dependent oxidation kinetics. At lower temperatures, the rate-determining step involved n-butanol oxidation, while at higher temperatures, simultaneous oxidation and desorption processes dominated. The calculated activation energy for the n-butanol oxidation step was 0.12 eV. Furthermore, principal component analysis (PCA) effectively discriminated n-butanol from other volatile organic compounds (VOCs), emphasizing the sensor's potential for selective n-butanol detection through a combination of kinetic modelling and statistical analysis.

Organic molecular design for high-power density sodium-ion batteries.

Organic materials, with abundant resources, low cost, high flexibility, tunable structures, lightweight nature, and wide operating temperature range, are regarded as promising candidates for sodium-ion batteries (SIBs). Unfortunately, their poor electronic and ionic conductivity remain significant challenges, hindering the achievement of high power density for sodium storage. Power density, a critical factor in battery performance evaluation, is essential for assessing fast charging capabilities. Therefore, it is essential to summarize strategies for high-power density SIBs in further development. To address these limitations and guide future development, this highlight summarizes key advancements in SIB research over the past decade. We outline the effective molecular design strategies for improving high-power-density sodium storage, with a focus on structural optimizations ranging from the backbone to the side chains. Additionally, we propose future perspectives on electrodes, electrolytes, and potential applications to enhance the power density of organic sodium-ion batteries. This review is intended to give a comprehensive guideline on the future design of organic materials for fast-charge ability and overall performance.

Highly linear wearable ionic gel based on self-assembled discoid liquid crystal towards human motion monitoring

The development of ionic gel with high flexibility, wide operating temperature range, and excellent physicochemical stability is crucial for the next generation of wearable flexible strain sensors. In this study,...