Wide Temperature Range Research Articles

Recycling of activated carbons from spent supercapacitors to refabricate improved supercapacitors

The growing market of commercial electric double-layer capacitors (EDLCs) will lead to a vast accumulation of waste as they arrive out of operation. Recycling the spent electrode activated carbon is a closed-loop solution to provide environmental and economic advantages for EDLC use. However, effectively regenerated methods of high-purity activated carbons are still lacked despite their considerable expense. Herein, a simple steam physical activation method is developed to regenerate high-class activated carbons from spent EDLCs. The process is first demonstrated that can effectively eliminate few electrolytes and complex organics as well as regenerate electrode carbon materials. The activation-recycled carbon materials preserve the physicochemical properties of fresh activated carbons and enhance their mesopore ratios, which contributes to improved EDLC performance, obviously surpassing recycled carbon materials by calcination method, including superior specific capacitance of 103.3 F g−1 at 0.5 A g−1, rate performance and cycling stability, equal to fresh activated carbons. Moreover, the assembled activation-recycled carbon material EDLC delivers low self-discharge rate (89 % of initial voltage after 72 h), wide temperature range (−40 to 85 °C), excellent cycling stability (92.2 % capacitance retention after 10,000 cycles) even at elevated voltages (3.0 V) and temperature (65 °C) test. The present work provides an effective and economic method of recycling high-grade activated carbons for sustainable EDLCs.

Enhancing the performance of ionic conductivity for solid-state electrolytes: an effective strategy of injecting lithium ions within anionic metal-organic frameworks.

Metal-organic frameworks (MOFs) are considered as potential solid-state electrolyte (SSE) materials due to their structural diversity and porosity. Adding lithium ions into the anionic frameworks of MOFs and then realizing single-ion transport is an efficient way to enhance the performance of ionic conductivity of SSE materials. Herein, an ionotropic MOF (Li+[Cu-BTC]-) with lithium ions in the pores of the lattice was synthesized through an ion exchange strategy, which exhibits outstanding lithium ionic conducting properties over a wide temperature range (ionic conductivity: 0.11-2.96 × 10-3 S cm-1 in the temperature range of -40 to 100 °C). The strategy of injecting Li+ within anionic metal-organic frameworks provides a new opportunity for exploring advanced SSEs.

Liquid Viscosity and Surface Tension of Cyclohexane Between 280 and 473 K by Surface Light Scattering

The present study provides experimental data for the liquid viscosity and surface tension of cyclohexane at or close to saturation conditions by surface light scattering between (280 and 473) K. By applying the hydrodynamic theory for surface fluctuations at the vapor–liquid phase boundary, which could be verified experimentally, the liquid viscosity and surface tension were determined simultaneously at macroscopic thermodynamic equilibrium with average relative expanded (k = 2) uncertainties of Ur(η′) = 0.020 and Ur(σ) = 0.012. For both properties, the present measurement results agree well with reference values in the literature which are restricted to a maximum temperature of 393 K for viscosity and 337 K for surface tension. The experimental results from this work contribute to an improved database for the viscosity and surface tension of cyclohexane over a wide temperature range from a temperature close to the melting point up to 473 K.

Taxonomic, Physiological, and Biochemical Characterization of Asterarcys quadricellularis AQYS21 as a Promising Sustainable Feedstock for Biofuels and ω-3 Fatty Acids

Asterarcys quadricellularis strain AQYS21, a green microalga isolated from the brackish waters near Manseong-ri Black Sand Beach in Korea, shows considerable potential as a source of bioactive compounds and biofuels. Therefore, this study analyzed the morphological, molecular, and biochemical characteristics of this strain; optimized its cultivation conditions; and evaluated its suitability for biodiesel production. Morphological analysis revealed characteristics typical of the Asterarcys genus: spherical to ellipsoidal cells with pyrenoid starch plates and mucilage-embedded coenobia. Additionally, features not previously reported in other A. quadricellularis strains were observed. These included young cells with meridional ribs and an asymmetric spindle-shaped form with one or two pointed ends. Molecular analysis using small-subunit rDNA and tufA sequences confirmed the identification of the strain AQYS21. This strain showed robust growth across a wide temperature range, with optimal conditions at 24 °C and 88 µmol m−2s−1 photon flux density. It was particularly rich in ω-3 α-linolenic acid and palmitic acid. Furthermore, its biodiesel properties indicated its suitability for biodiesel formulations. The biomass of this microalga may serve as a viable feedstock for biodiesel production and a valuable source of ω-3 fatty acids. These findings reveal new morphological characteristics of A. quadricellularis, enhancing our understanding of the species.

Large Room-Temperature Electrocaloric Effect in Lead-Free Relaxor Ferroelectric Ceramics with Wide Operation Temperature Range

In order to obtain large room-temperature electrocaloric effect (ECE) and wide operation temperature range simultaneously in lead-free ceramics, we proposed designing a relaxor ferroelectric with a Tm (the temperature at which the maximum dielectric permittivity is achieved) near-room temperature and glass addition. Based on this strategy, we designed and fabricated lead-free 0.76NaNbO3–0.24BaTiO3 (NN-24BT) ceramics with 1wt.% BaO–B2O3–SiO2 glass addition, which showed distinct relaxor ferroelectric characteristics with strongly diffused phase transition and a Tm near-room temperature. Based on a direct measurement method, a large ΔT (adiabatic temperature change) of 1.3 K was obtained at room temperature under a high field of 11.0 kV mm−1. Additionally, large ECE can be maintained (>0.6 K@6.1 kV mm−1) over a broad temperature range from 23 °C to 69 °C. Moreover, the ECE displayed excellent cyclic stability with a variation in ΔT below ±7% within 100 test cycles. The comprehensive ECE performance is significantly better than other lead-free ceramics. Our work provides a general and effective approach to designing lead-free, high-performance ECE ceramics, and the approach possesses the potential to be utilized to improve the ECE performance of other lead-free ferroelectric ceramic systems.

Aqueous Supercapacitor with Wide-Temperature Operability and over 100,000 Cycles Enabled by Water-in-Salt Electrolyte.

Supercapacitors are crucial in renewable energy integration, satellite power systems, and rapid power delivery applications for mitigating voltage fluctuations and storing excess energy. Aqueous electrolytes offer a promising solution for low-cost and safe supercapacitors. However, they still face limitations in cycle life and wide-temperature range performance. Here, we present a symmetric supercapacitor utilizing activated carbon electrodes and a "water-in-salt" electrolyte (WiSE) based on lithium perchlorate. The WiSE electrolyte exhibits an expanded electrochemical stability window, endowing the aqueous supercapacitor with remarkable stability and long cycle life of over 100,000 cycles at 500 mA g-1 with more than 91% capacity retention. Moreover, the supercapacitor demonstrates good rate capability and wide temperature operability ranging from -20 to 80 °C. The use of high concentrations of salt in the aqueous electrolyte contributes not only to the enhancement of supercapacitor performance and cycle life but also to the temperature stability range, enabling all-season operability.

Synergistic Anion and Solvent-Derived Interphases Enable Lithium-Ion Batteries under Extreme Conditions.

Lithium-ion batteries (LIBs) face increasingly stringent demands as their application expands into new areas, including extreme temperatures and fast charging. To meet these demands, the electrolyte should enable fast lithium-ion transport and form stable interphases on electrodes simultaneously. In practice, however, improving one aspect often compromises another. For instance, the trend toward electrolytes forming anion-derived interphases typically reduces transport efficiency due to weak-solvating solvents. We propose that instead of relying on anions to form the interphase, leveraging both solvents and anions to form interphases can potentially lead to a balancing point between robust interphase formation and effective ion transport. Guided by this design principle, 2,2-difluoroethyl ethyl carbonate (DFDEC) was identified as the promising solvent. With the new electrolyte using DFDEC as the major solvent and lithium bis(fluorosulfonyl) imide (LiFSI) as the salt, graphite||LiNi0.8Mn0.1Co0.1O2 (NMC811) full cells are capable of fast charging and demonstrate long-term cycling stability with a cutoff voltage of 4.5 V. Notably, the battery shows a capacity retention of 84.3% after 500 cycles with an average Coulombic efficiency (CE) as high as 99.93%. This new electrolyte also enables stable battery cycling across a wide temperature range (-20 to 60 °C), with excellent capacity retention.

A Rapid Synthesis of Amorphous LiTaOCl4 Solid Electrolytes Through a Two‐Step Reaction Pathway for High‐Rate and Long‐Cycling Lithium Batteries

AbstractA simplified process to prepare solid electrolytes (SEs) that fulfill long cyclability, fast‐charging performance, and wide‐temperature feasibility in all‐solid‐state lithium batteries (ASSLBs) is important. Here, amorphous LiTaOCl4 (aLTOC) SE is synthesized within only four hours via a two‐step reaction by high‐energy ball milling method, which exhibits high ionic conductivity and excellent interfacial compatibility. A bilayer SE based on aLTOC and sulfide along with corresponding ASSLBs, are constructed. Furthermore, slight evolution of the unusual microstructure in the chloride/sulfur interfacial region is observed and analyzed. Density functional theory calculations show that S tends to displace O sites in TaO2Cl4 octahedra instead of Cl sites. As a result of the enhanced interfacial stability and reduced formation of ionically insulating phases, the assembled ASSLBs achieve superior rate performance and cyclability in a wide temperature range. Notably, the ASSLBs show capacity retention of 84.4% and 77.6% after 2000 and 1000 cycles at current density of 10C at 30 and 60 °C, respectively. Importantly, even under −20 °C, the cell works stably over 1600 cycles with capacity retention of 76.3% at 0.5C. The work pave the way for the massive production of high‐performance amorphous chloride electrolytes and the realization of fast‐charging ASSLBs with long cycle life.

Broad-Temperature Thermoelectric Figure of Merit Enhancement in Unconventional n-Type Bi2Te2.3Se0.7 Alloys.

Bi2Te2.7Se0.3-based alloys are conventional n-type thermoelectric materials for solid-state cooling and heat harvest near room temperature; high thermoelectric performance over a wide temperature range and superior mechanical properties are essential for their use in practical thermoelectric devices. In this work, we demonstrated that decent thermoelectric performance can also be realized in an unconventional composite with a nominal composition of Bi2Te2.3Se0.7 since the emergence of a Bi2Te2Se phase with Se ordered occupation could induce an enlargement of the electronic band gap. Follow-up Cu/Na codoping could generate a dynamic optimization of carrier concentration, significantly broadening the temperature range of high thermoelectric performance. Further B incorporation and annealing treatment resulted in obvious grain refinement and stacking fault structures, which help pushing the ultimate maximal figure of merit up to ∼1.3 at 423 K with an average value of ∼1.2 at 300-573 K. This work might provide insights for further research on bismuth tellurides and other thermoelectric materials.

The Catalytic Mechanisms and Design Strategies of Noble Metal Catalysts for Selective Reduction of NOx with CO

AbstractThe selective catalytic reduction of NOx by CO (CO‐SCR) is a viable method for simultaneously mitigating NOx and CO emissions in motor vehicle exhaust and industrial flue gases. Extensive research has been conducted on noble metal catalysts because of their superior catalytic activity and stability compared to non‐noble metals. Noble metal catalysts demonstrate efficient NOx conversion and high selectivity for N2. However, achieving high conversion, selectivity, and stability over a wide temperature range in the presence of excess O2, H2O, and SO2 remains a significant challenge. This review summarizes recent advancements in CO‐SCR over noble metal catalysts, providing insights for the development of CO‐SCR catalysts. This paper first examines the reaction mechanisms of CO‐SCR, followed by a discussion on the design and optimization strategies of noble metal catalysts, with a focus on composition and structural effects. This includes creating active metal sites, selecting appropriate supports, integrating catalytic additives, choosing monometallic nanoparticles, alloying, and using single‐atom catalysts. Finally, remaining challenges and potential avenues for future research have been suggested. The discovery of negatively charged noble metal single‐atom‐site catalysts presents new research opportunities.

Non‐Fluorinated Cyclic Ether‐Based Electrolyte with Quasi‐Conjugate Effect for High‐Performance Lithium Metal Batteries

AbstractFluorinated ether‐based electrolytes are commonly employed in lithium metal batteries (LMBs) to attenuate the coordination ability of ether solvents with Li+ and induce inorganic‐rich interphase, whereas fluorination inevitably introduces exorbitant production expenses and environmental anxieties. Herein, a non‐fluorinated molecular design strategy has been conceptualized by incorporating methoxy as an electron‐donating group to generate a quasi‐conjugate effect for tuning the affinity of Li+‐solvent, thereby enabling the cyclic ether solvent 2‐methoxy‐1,3‐dioxolane with weak solvation ability and exceptional Li metal‐compatibility. Accordingly, the optimized electrolyte exhibits anion‐dominant solvation structure for inorganic‐rich interphase and fulfills an impressive Li plating/stripping Coulombic efficiency of 99.6 %. As‐fabricated Li||LiFePO4 full cells with limited Li (N/P=2.5) showcase a high capacity retention of 83 % after 150 cycles, indicating excellent cycling stability. Moreover, the full LMBs demonstrate exceptional tolerance towards a wide temperature range from −20 °C to 60 °C, displaying a remarkable capacity retention of 90 % after 110 cycles at −20 °C. Such a molecular design strategy offers a promising avenue for electrolyte engineering beyond fluorination in order to cultivate high‐performance LMBs.

High-Entropy Magnet Enabling Distinctive Thermal Expansions in Intermetallic Compounds.

The high-entropy strategy has gained increasing popularity in the design of functional materials due to its four core effects. In this study, we introduce the concept of a "high-entropy magnet (HEM)", which integrates diverse magnetic compounds within a single phase and is anticipated to demonstrate unique magnetism-related properties beyond that of its individual components. This concept is exemplified in AB2-type layered Kagome intermetallic compounds (Ti,Zr,Hf,Nb,Fe)Fe2. It is revealed that the competition among individual magnetic states and the presence of magnetic Fe in originally nonmagnetic high-entropy sites lead to intricate magnetic transitions with temperature. Consequently, unusual transformations in thermal expansion property (from positive to zero, negative, and back to near zero) are observed. Specifically, a near-zero thermal expansion is achieved over a wide temperature range (10-360 K, αv = -0.62 × 10-6 K-1) in the A-site equal-atomic ratio (Ti1/5Zr1/5Hf1/5Nb1/5Fe1/5)Fe2 compound, which is associated with successive deflection of average Fe moments. The HEM strategy holds promise for discovering new functionalities in solid materials.

Tailoring eco-friendly siloxane-based electrolytes for high-performance lithium–sulfur batteries

Lithium–sulfur batteries (LSBs), with their ultra-high theoretical energy density (2600 Wh kg−1), are considered one of the most attractive high-energy batteries. However, the “shuttling effect” of polysulfides and the uncontrolled growth of lithium (Li) dendrites pose significant challenges to the practical implementation of LSBs. Herein, a lightweight and eco-friendly diethoxydimethylsilane (DEMS) is chosen as a multi-functional solvent for LSBs. The low polarity of DEMS promotes the “solid–solid” conversion of sulfurized polyacrylonitrile (SPAN) during charge–discharge processes, eliminating the shuttle effect of polysulfides. Moreover, the DEMS-based electrolyte enables highly reversible Li plating/stripping processes across a wide temperature range spanning from −20 to 60 °C. As a result, the Li/SPAN batteries using the DEMS electrolyte exhibit excellent cyclic stability at 0.2 C with retainable capacities of 524.4 mAh/g after 200 cycles, 598.8 mAh/g after 100 cycles, and 318.6 mAh/g after 50 cycles at 26, 60 and −20 °C, respectively. This study aims to identify low-cost and highly stable electrolytes through solvent screening to enhance the electrochemical performance of LSBs.

Impact ionization coefficients along 4H-SiC ⟨11-20⟩ in a wide temperature range

Abstract The impact ionization coefficients along 4H-SiC ⟨11-20⟩ were determined in a wide temperature range from 294 K to 473 K. 4H-SiC (11-20) p-n diodes were fabricated and photomultiplication measurements were conducted on two types of photodiodes to measure the multiplication factors of carriers. The extracted impact ionization coefficients of both electrons and holes along 4H-SiC ⟨11-20⟩ decreased at high temperatures, which can be ascribed to the enhanced phonon scattering. On the basis of the results above, the critical electric field along 4H-SiC ⟨11-20⟩ calculated from the obtained impact ionization coefficients increased with the temperature.

Metal substrate printed circuit boards as low-cost, robust temperature sensor mounts for cryogenic thermometry

Abstract Cryogenic experiments strongly depend on accurate temperature measurements. Many of the sensors used for these purposes are glued to the object to be measured to achieve adequate thermal contact. This calls for a more flexible, long lasting and robust bolt-mounted solution. Therefore, we present a low-cost ($<$ 5\$), compact, PCB (printed circuit board) based sensor mount for RTDs (resistance temperature detector) and diodes showing reliable results at temperatures from 50 K to 400 K with possible modifications for an extended range down below 20 K. We anticipate that the robustness and low cost of the reported sensor mount design will strongly enhance the accessibility of reliable temperature measurements at a wide range of temperatures in laboratory applications.

Searching for a Lifshitz point in the magnetic phase diagram of UNi2Si2

A single crystal of UNi2Si2 has been grown by the Czochralski pulling technique. Its physical properties have been studied over a wide range of temperatures and magnetic field strengths. The main aim of the studies was to construct a magnetic phase diagram of the compound in order to verify the hypothesis of the existence of a Lifshitz point in it. Our studies showed that the boundaries between paramagnetic, modulated and uniform magnetic phases do not merge up to 14 T.

Overaging in Glassy Polymers within a Wide Range of Temperature

Overaging in Glassy Polymers within a Wide Range of Temperature

Crystals of para-quaterphenyl and its trimethylsilyl derivative. I. Growth from solutions, structure and crystal chemical analysis by the Hirschfeld surface method

The results of crystal growth of para-quaterphenyl (4P) and its derivative – 4,4''-bis(trimethylsilyl)-para-quaterphenyl (TMS-4P-TMS) from solutions are presented. It has been established that TMS-4P-TMS crystals exhibit better growth characteristics compared to 4P. Parameters of phase transitions of 4P and TMS-4P-TMS in closed crucibles were refined using the method of differential scanning calorimetry. The crystal structure of TMS-4P-TMS in the triclinic space group P1 (Z = 2) has been decrypted for the first time using single-crystal X-ray diffraction and studied over a wide temperature range. Crystallographic analysis of the studied compounds in crystals was performed using the Hirshfeld surface method, and modeling of intermolecular interactions was conducted.

High Temperature-Insensitive Electrostrain Obtained in (K, Na)NbO3-Based Lead-Free Piezoceramics.

Over the last decades, notable progress is achieved in (K, Na)NbO3 (KNN)-based lead-free piezoceramics. However, more studies are conducted to increase its piezoelectric charge coefficient (d33). For actuator applications, piezoceramics need high electric-field induced strain under low electric fields while maintaining exceptional temperature stability across a wide temperature range. In this study, this work developes Li/Sb-codoped KNN (LKNNS) ceramics with high electrostrain by defect engineering and domain engineering. A remarkable strain of 0.43%, along with a giant d33* value of 2177 pm V-1, is attained in the LKNNS ceramic at 20 kV cm-1. The ceramic exhibits a minimal performance decrease of less than 15% over a temperature range from room temperature to 150 °C. The exceptional strain is attributed to the presence of A-site vacancy-oxygen vacancy ( ) defect dipoles and the increase in nano-domains. The hierarchical domain configuration and defect dipoles impede the switched domains from reverting to their original state as temperature increases, furthermore, the elongated dipole moments of caused by rising temperatures compensate for strain reduction results in exceptional temperature stability. This study provides a model for designing piezoelectric materials with exceptional overall performance under low electric fields and across a wide temperature range.

Phase behavior of metastable water from large-scale simulations of a quantitatively accurate model near ambient conditions: The liquid-liquid critical point.

The molecular mechanisms of water's unique anomalies are still debated upon. Experimental challenges have led to simulations suggesting a liquid-liquid (LL) phase transition, culminating in the supercooled region's LL critical point (LLCP). Computational expense, small system sizes, and the reliability of water models often limit these simulations. We adopt the CVF model, which is reliable, transferable, scalable, and efficient across a wide range of temperatures and pressures around ambient conditions. By leveraging the timescale separation between fast hydrogen bonds and slow molecular coordinates, the model allows a thorough exploration of the metastable phase diagram of liquid water. Using advanced numerical techniques to bypass dynamical slowing down, we perform finite-size scaling on larger systems than those used in previous analyses. Our study extrapolates thermodynamic behavior in the infinite-system limit, demonstrating the existence of the LLCP in the 3D Ising universality class in the low-temperature, low-pressure side of the line of temperatures of maximum density, specifically at TC = 186 ± 4 K and PC = 174 ± 14 MPa, at the end of a liquid-liquid phase separation stretching up to ∼200 MPa. These predictions align with recent experimental data and sophisticated models, highlighting that hydrogen bond cooperativity governs the LLCP and the origin of water anomalies. We also observe substantial cooperative fluctuations in the hydrogen bond network at scales larger than 10nm, even at temperatures relevant to biopreservation. These findings have significant implications for nanotechnology and biophysics, providing new insights into water's behavior under varied conditions.