Wide Operating Temperature Range Research Articles

Fabrication of NiC2O4/PANI heterojunction structure on carbon cloth for neutral electrolyte supercapacitor application

Despite the wider potential windows and environmental friendliness provided by neutral electrolyte systems in supercapacitors, lower specific capacitance was often observed due to the absence of highly active pseudocapacitive reactions on the electrode surface. Introducing pseudocapacitive reactions from the electrode interior by constructing heterojunctions could be a promising solution to address this challenge. In this study, a NiC2O4/PANI heterojunction structure was constructed on carbon cloth using an in-situ method. The electrode exhibited excellent specific capacitance (1.70F cm−2 at 2 mA cm−2) and potential window (-0.5 V to 1.2 V). Impedance analysis and the two-probe IV method further confirm the presence and effectiveness of the heterojunction in enhancing the electrode's electrochemical performance. Additionally, this electrode also demonstrated outstanding cycling stability, reproducibility, and a wide operating temperature range. The successful development of the NiC2O4/PANI heterojunction structure on carbon cloth offered valuable insights into the design and fabrication of advanced supercapacitor applications.

Droplet freezing assays using a nanoliter osmometer

The ability to accurately record the temperature at which ice nucleation occurs is critical for studying biological ice nucleators. Several instruments have been designed and custom built to make such measurements, but they are not yet on the market. Here we reproducibly measure ice nucleation temperatures down close to the homogeneous nucleation temperature of −38 °C with a commercially available nanoliter osmometer, which we routinely use to assay the thermal hysteresis activity of antifreeze proteins. This instrument has both a wide operating temperature range and fine temperature control, while the oil immersion format on 12-well grids prevents droplet evaporation and surface nucleation events. The results obtained are consistent with those reported on other instruments in common use.

Haze-Suppressed Wideband Light Shutter from Near Ultraviolet to Infrared Rays Utilizing Electrophoretic Carbon Black Particles.

Carbon black (CB) particles that can absorb from near ultraviolet to infrared rays are well dispersed into an isotropic dielectric liquid and their optical properties can be kept even under exposure to sunlight over a long time. The shutter which controls the position of CB particles by electrophoretic force can be applied to switchable light shutters for windows in buildings and automobiles for the purpose of energy savings. Here, a wideband light shutter with three terminal electrodes is proposed, exhibiting excellent dark (transmittance ≈1.4%) and transparent state (transmittance >60%). The device operates at a low field intensity of about 1Vµm-1 to obtain transparent state and its wide temperature range operation from -50 to 120°C is confirmed while conventional liquid crystal-based shutter cannot perform such levels due to a limited temperature range in the nematic phase. In addition, haze is minimized in a transparent state by adopting an insulation layer over electrodes and a solution is found to keep a transparent state without applying power. It is believed that the proposed broadband shutter with fast response time could open a new chapter in switchable windows owing to its low power consumption and working in a wide temperature range.

In-situ prelithiation of electrolyte-free silicon anode for sulfide all-solid-state batteries

All-solid-state batteries (ASSBs) based on silicon (Si) anodes offer high energy density and safety, which are considered promising next-generation energy-storage systems. However, the large initial capacity loss of Si anodes greatly limits the practical capacity and rate performance of ASSBs. Herein, through the unique in-situ prelithiation of electrolyte-free Si anodes by using ultra-thin lithium (Li) foil, the Li6PS5Cl electrolyte-based ASSBs achieve significantly improved initial Coulombic efficiencies (ICEs). The results of three-electrode ASSBs confirm that the in-situ prelithiation strategy effectively improves the reversible delithiation capacity and solid-state Li kinetics of electrolyte-free Si anode. The full cells utilizing prelithiated Si anode and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode exhibit a remarkable energy density of 402 Wh kg−1 (based on the total mass of cathode and anode) at 0.1 C and achieve a wide operating temperature range between −30 and 50 °C. In addition, the bi-polar stacking cell with high-loading NCM811 cathode achieves a high cut-off voltage of 8.7 V and works stable for over 50 cycles. This practical prelithiation method presents substantial advantages to promote the development of ASSBs based on Si anodes with high ICEs and fast Li kinetics, offering a pathway to realize solid-state storages with high rates and high energy densities.

The Effect of Microwave Irradiation on the Synthesis of Graphene from Battery Waste on Capacitance Properties

Supercapacitor material is an alternative in energy storage. Supercapacitors are charge storage devices that have a high energy density, fast charge/discharge rates, long service life, wide operating temperature range, and are environmentally friendly. Graphene is a nanomaterial that can be used as a supercapacitor because it has high conductivity and a large surface area, but graphene can experience agglomeration so it can affect its capacitance properties. The microwave-assisted method can be used in the synthesis of graphene. Several microwave-based techniques are becoming more popular for producing graphene and altering it. Due to its quick, precise, uniform, and volumetric heating, microwave heating is a promising method for the thermochemical treatment and reduction of graphene oxide to graphene. This research aimed to examine the effect of microwave irradiation time on the capacitive properties of graphene synthesis as a supercapacitor. Graphene oxide (GO) can be reduced into graphene quickly and easily using microwave pulses lasting 15 to 30minutes to produce high-quality graphene fabrication. The characterization test was performed using UV-Vis, FTIR, SEM-EDX and cyclic voltammetry (CV). As a result, the optimum time is 25 minutes, and it showed an absorption peak at the 282 nm wavelength dan the CV analysis showed that the graphene has double capacitor properties with a specific capacitance of 140.7 F/g in 20 mV/s. Besides, the result of SEM indicated that graphene could be formed successfully. Its potential applications are also illustrated by emphasizing its usage as electrode material. Finally, its main challenges and prospects are considerably pointed out.

Energetic macroscopic representation of a mechanical compression-assisted hybrid thermochemical cycle exploiting low grade heat for cold applications

This paper describes an original model based on The Energetic Macroscopic Representation (EMR) to develop a control structure of an innovative compression-assisted hybrid thermochemical cooler driven by low-grade thermal energy. Hybrid thermochemical cooler with mechanical compression have a wider operating temperature range than conventional thermochemical processes. This makes it possible to exploit lower grade heat sources and/or produce cold at lower temperatures. In addition, the ability to control compressor speed increases thermochemical process controllability to respond to load or source variations. Nodal modeling of each process component is developed according to the EMR formalism. A parametric identification and validation of this process model is then carried out using experimental data. The deviation from the experimental data is lower than 1bar for the reactor, condenser and evaporator pressure, lower than 0.1 for the reaction advancement and lower than 2°C for the reactor wall temperature. The EMR model is then inverted to obtain a process control law for maintaining a cold room at -18°C. Despite the variation in cooling demand from a minimum of 100W to a maximum of 700W, the compressor's control structure was able to regulate its speed of rotation to maintain the cold room temperature at -18±0.5°C for 24h.

Fabrication of Gelatin-Derived Gel Electrolyte Using Deep Eutectic Solvents through In Situ Derivatization and Crosslinking Strategy for Supercapacitors and Flexible Sensors.

The facile fabrication of gel polymer electrolytes is crucial to the development of flexible electronics, and the use of natural polymers as sources has obtained great attention due to their abundant, low-cost, biodegradable, easy modification, and biocompatible features. In this article, a facile fabrication protocol to engineer gelatin into gel electrolytes was developed by taking the advantages of both deep eutectic solvent (DES) (including its good solubility to gelatin and satisfactory electrochemical properties) and rich active functional groups of gelatin, through in situ derivatization and crosslinking strategy. A double-crosslinked DES gel electrolyte was prepared with the dissolution of gelatin in choline chloride and alcohol-based DES and a further crosslinking with Fe3+ ions. The obtained DES gel presented outstanding mechanical properties, excellent ionic conductivity (up to 101-102 mS/cm), a wide operating temperature range (-40 to 80 °C), satisfactory self-healing property, and good degradability. Moreover, the obtained DES gel electrolyte was successfully applied to supercapacitors and flexible sensors, showing excellent electrochemical performance and strain-response properties. In a word, our study provides a facile protocol to engineer gelatin into gel electrolytes by using deep eutectic solvent, showing significant insights into the design and preparation of sustainable gel polymer electrolytes and having great application potential in next-generation high-performance flexible electronics.

High-Performance Lithium-Sulfur Batteries via Molecular Complexation.

Beyond lithium-ion technologies, lithium-sulfur batteries stand out because of their multielectron redox reactions and high theoretical specific energy (2500 Wh kg-1). However, the intrinsic irreversible transformation of soluble lithium polysulfides to solid short-chain sulfur species (Li2S2 and Li2S) and the associated large volume change of electrode materials significantly impair the long-term stability of the battery. Here we present a liquid sulfur electrode consisting of lithium thiophosphate complexes dissolved in organic solvents that enable the bonding and storage of discharge reaction products without precipitation. Insights garnered from coupled spectroscopic and density functional theory studies guide the complex molecular design, complexation mechanism, and associated electrochemical reaction mechanism. With the novel complexes as cathode materials, high specific capacity (1425 mAh g-1 at 0.2 C) and excellent cycling stability (80% retention after 400 cycles at 0.5 C) are achieved at room temperature. Moreover, the highly reversible all-liquid electrochemical conversion enables excellent low-temperature battery operability (>400 mAh g-1 at -40 °C and >200 mAh g-1 at -60 °C). This work opens new avenues to design and tailor the sulfur electrode for enhanced electrochemical performance across a wide operating temperature range.

Construction of high-rate performance sulfurized Poly(acrylonitrile) nanofibers cathodes for practical lithium–sulfur batteries via tellurium catalytic regulation

The rapid charge-discharge and wide operating temperature range are of great significance to the research of lithium-sulfur batteries. However, the poor electronic and ionic conductivity of sulfurized polyacrylonitrile limits the high-rate and low-temperature performance of lithium-sulfur batteries. In this work, a tellurium-doped sulfurized polyacrylonitrile nanofibers-based cathode material (Te0.02S0.98FPAN) is successfully fabricated by air-blow spinning for lithium-sulfur batteries. It is found that Te0.02S0.98FPAN maintained a high reversible specific capacity of 742 mAh·g−1composites after 200 cycles at a current density of 0.2 C (0.014% decay per cycle), whereas it provides a reversible specific capacity of 641 mAh·g−1composites after 500 cycles even at a large current density of 1.0 C (0.021% decay per cycle), manifesting its excellent high-rate performance. Moreover, Te0.02S0.98FPAN still maintained a high reversible specific discharge capacity of 586 mAh·g−1composites after 100 cycles at 0.2 C at a low temperature of 5.0 °C, confirming its wide operating temperature range. Both the eutectic accelerator (tellurium) and the one-dimensional nanofibrous structure greatly improve the migration rate and electron transport ability of Li+ ions, enhancing reaction kinetics and providing fast and stable migration channels for ions and electrons. Therefore, Te0.02S0.98FPAN has a higher oxidation-reduction reaction rate and less polarization. This study not only provides new ideas for the cathode design of lithium-sulfur batteries with high rate and wide temperature range, but also paves the way for the development of practical lithium-sulfur batteries. In particular, when tested in practical conditions of high areal loading (Te0.02S0.98: 5.0 mg cm−2) and lean electrolyte (E/Te0.02S0.98: 10 μL mg−1), this cathode delivers high reversible capacities of 725 mAh g−1 composite (0.1 C) and 663 mAh g−1 composite (0.2 C), demonstrating its great potential for future application.

Non-flammable solvent-free liquid polymer electrolyte for lithium metal batteries

As a replacement for highly flammable and volatile organic liquid electrolyte, solid polymer electrolyte shows attractive practical prospect in high-energy lithium metal batteries. However, unsatisfied interface performance and ionic conductivities are two critical challenges. A common strategy involves introducing organic solvents or plasticizers, but this violates the original intention of security design. Here, an electrolyte concept called liquid polymer electrolyte without any small molecular solvents is proposed for safe and high-performance batteries, based on the design of a room-temperature liquid-state brush-like polymer as the sole solvent of lithium salts. This liquid polymer electrolyte is non-flammable and exhibits high ionic conductivity (1.09 times 10−4 S cm−1 at 25 °C), significant lithium dendrite suppression, and stable long-term cycling over a wide operating temperature range ( ≥ 1000 cycles at 60 °C and 90 °C). Moreover, the pouch cell can resist thermal abuse, vacuum environment, and mechanical abuse. This electrolyte and design strategy are expected to provide enlightening ideas for the development of safe and high-performance polymer electrolytes.

Influence of mechanical stress on electron transport properties of second-generation high-temperature superconducting tapes

Second-generation high-temperature superconductor (2G HTS) tapes have demonstrated the ability to generate high magnetic fields and critical currents at a wide operating temperature range. In this paper, we study the mechanical properties of 2G HTS tape measured simultaneously with its critical current. The lattice deformations in the tape’s substrate caused by applied mechanical stress were measured by neutron diffraction. In our experiments, the 2G HTS tape was exposed to uniaxial tensile force ranging from 250 to 1100 N at temperature 77 K. The current through the tape was scanned in the range from 22 to 42 A. The experimental results have been obtained in a cryogenic testing chamber for neutron scattering measurements of internal stresses under load with the incorporated HTS current leads. Critical stress is a vital parameter required for the modeling and designing of advanced superconducting magnets and also a variety of different superconducting applications based on 2G HTS tapes.

Robust iron-based cathode for ultralong-lasting Na-ion battery with a wide operation-temperature

Na4Fe3(PO4)2(P2O7) (NFPP) is an attractive cathode material for sodium-ion batteries (SIBs) due to its low-cost, robust framework, and cross-linked Na+ migrate channels. However, the real implementation of NFPP remains in its infancy, mainly hindered by the inferior intrinsic electronic conductivity. Herein, a doping strategy by incorporating manganese into NFPP lattice (NFMPP) is proposed to lower the band gap and Na+ migrate barriers, thus ultimately rendering robust ligand framework, improved electronic transmission and fast ions diffusion. Greatly, the ultralong-lasting cyclability (88.1% capacity retention for over 10000 cycles at 50 C), impressive rate capability (42.7 mAh g−1 at 200 C), and decent electrochemical performance over a wide operation-temperature range from − 40–60 ℃ are achieved. The structural evolution and charge compensation mechanism during cell operation are systematically explored utilizing in situ X-ray diffraction (XRD) and X-ray absorption near edge structure (XANES) measurements, confirming a minimized volume fluctuation and highly reversible Fe2+/Fe3+ redox reaction. Full cell comprising a NFMPP cathode and pre-sodiated hard carbon anode is also yielded as proof of concept. The superior electrochemical performances, and the insertion/extraction mechanism investigation sheds light to the feasibility of utilizing NFMPP as a cathode material for low-cost and high-performance gride-scale energy storage systems (EESs).

A High-Sensitivity Cesium Atomic Magnetometer Based on A Cesium Spectral Lamp

Based on a low-noise cesium spectral lamp, a high-sensitivity self-oscillating cesium atomic magnetometer with a wide operating temperature range has been developed, solving problems with existing sensors such as a limited operating temperature range and difficult startup at low temperatures. The temperature feedback mechanism is used to make adjustments to any fluctuations in the cesium lamp’s excitation source in real time, improving the magnetometer’s stability and operating temperature range. Herein, the design and optimization of the cesium atomic magnetometer are presented, and a prototype of the magnetometer is described. The quantum limit sensitivity of the cesium atomic magnetometer is estimated by evaluating the intrinsic relaxation rate in the geomagnetic field. A test demonstrates that the cesium atomic magnetometer’s sensitivity in the geomagnetic background is around 140 fT/Hz at 1 Hz at room temperature, and the operating temperature range is from −50 °C to 70 °C, surpassing most of the commercial products of its kind in terms of sensitivity and operating temperature range.

“Deep Eutectic Solvent-in-Water” Hydrogels Enable High-Performance Flexible Strain Sensors for Electronic Skin with a Wide Operating Temperature Range

“Deep Eutectic Solvent-in-Water” Hydrogels Enable High-Performance Flexible Strain Sensors for Electronic Skin with a Wide Operating Temperature Range

Design and construction of low resistance copper doped polyaniline electrode with ultrahigh loading density for high performance supercapacitor applications

Polyaniline is a promising material for the development of high performance flexible supercapacitor devices. However, the loose structure of polyaniline materials and the high intermolecular transport impedance between molecular chains remain significant technical barriers, particularly at high loading density. In this study, we developed a copper ion doped polyaniline electrode (Cu-PANI@CC) on carbon cloth using a simple one-step in-situ electrochemical deposition method. The structure and electrochemical properties of this electrode were investigated via different testing techniques. Benefiting from the catalysis and regulation of copper ions between PANI molecular chains, the electrode demonstrated a relatively low internal resistance at high loading densities (> 10 mg cm−2). Moreover, this electrode exhibited specific capacitance of 3.49 F cm−2 at 5 mA cm−2 and capacitance retention of 83.31% at 50 mA cm−2. Two Cu-PANI@CC electrodes were used to fabricate a symmetrical capacitor, which exhibited remarkable cycling stability and wide operating temperature range. The excellent electrochemical performance of the Cu-PANI@CC electrode highlights the potential for use in high-performance supercapacitor devices.

Improvement of Hybrid Electrode Material Synthesis for Energy Accumulators Based on Carbon Nanotubes and Porous Structures.

Carbon materials are promising for use as electrodes for supercapacitors and lithium-ion batteries due to a number of properties, such as non-toxicity, high specific surface area, good electronic conductivity, chemical inertness, and a wide operating temperature range. Carbon-based electrodes, with their characteristic high specific power and good cyclic stability, can be used for a new generation of consumer electronics, biomedical devices and hybrid electric vehicles. However, most carbon materials, due to their low electrical conductivity and insufficient diffusion of electrolyte ions in complex micropores, have energy density limitations in these devices due to insufficient number of pores for electrolyte diffusion. This work focuses on the optimization of a hybrid material based on porous carbon and carbon nanotubes by mechanical mixing. The purpose of this work is to gain new knowledge about the effect of hybrid material composition on its specific capacitance. The material for the study is taken on the basis of porous carbon and carbon nanotubes. Electrodes made of this hybrid material were taken as an object of research. Porous carbon or nitrogen-containing porous carbon (combined with single-, double-, or multi-layer carbon nanotubes (single-layer carbon nanotubes, bilayer carbon nanotubes or multilayer carbon nanotubes) were used to create the hybrid material. The effect of catalytic chemical vapor deposition synthesis parameters, such as flow rate and methane-to-hydrogen ratio, as well as the type of catalytic system on the multilayer carbon nanotubes structure was investigated. Two types of catalysts based on Mo12O28 (μ2-OH)12{Co(H2O)3}4 were prepared for the synthesis of multilayer carbon nanotubes by precipitation and combustion. The resulting carbon materials were tested as electrodes for supercapacitors and lithium ion intercalation. Electrodes based on nitrogen-containing porous carbon/carbon nanotubes 95:5% were found to be the most efficient compared to nitrogen-doped porous carbon by 10%. Carbon nanotubes, bilayer carbon nanotubes and multilayer carbon nanotubes synthesized using the catalyst obtained by deposition were selected as additives for the hybrid material. The hybrid materials were obtained by mechanical mixing and dispersion in an aqueous solution followed by lyophilization to remove water. When optimizing the ratio of the hybrid material components, the most effective porous carbon:carbon nanotubes component ratio was determined.

Mo-doped MnO2@CC electrode for high-performance 2.4 V aqueous asymmetric supercapacitors

Despite many advantages of supercapacitors based on aqueous electrolytes, the inherently low operating voltage severely limits their energy density and practical applicability to many applications. Thus, it is a key scientific challenge to broaden the potential window of electrode materials for supercapacitors. Here we report our findings in tailoring the Fermi level of MnO2-based electrode by doping with a high-valence Mo6+ ion, thus modulating its overpotential in aqueous electrolytes and potential window. For example, the redox potential of Mo-doped MnO2 is effectively increased, resulting in a wider potential window. When grown on a carbon support, the specific capacitance of Mo-doped MnO2@CC with a mass loading of 15.1 mg cm−2 reaches 3.22 F cm−2 in a wide potential window of 1.2 V. The enhanced performance is attributed to the additional redox behavior induced by the Mo dopant, as confirmed by in situ Raman and ex-situ XPS analyses. When coupled with a C-Ti3C2Tx/WO3@CC negative electrode to construct an ASC with a total mass loading of 35.8 mg cm−2, the ASC exhibits a wide voltage window of 2.4 V, demonstrating a remarkable energy density of 0.89 mWh cm−2 at a power density of 2.56 mW cm−2. In addition, the device is operational in a wide operating temperature range of −10 to 50 °C, and a voltage of ∼ 58% is retained after self-discharge for 48 h. This work provides some new insights into the development of aqueous ASC devices of commercial-grade mass loadings with high output voltage, high energy density, and slow self-discharge rates.

High Sensitivity Low-Temperature Hydrogen Sensors Based on SnO2/κ(ε)-Ga2O3:Sn Heterostructure

The structural and gas-sensitive properties of n-N SnO2/κ(ε)-Ga2O3:Sn heterostructures were investigated in detail for the first time. The κ(ε)-Ga2O3:Sn and SnO2 films were grown by the halide vapor phase epitaxy and the high-frequency magnetron sputtering, respectively. The gas sensor response and speed of operation of the structures under H2 exposure exceeded the corresponding values of single κ(ε)-Ga2O3:Sn and SnO2 films within the temperature range of 25–175 °C. Meanwhile, the investigated heterostructures demonstrated a low response to CO, NH3, and CH4 gases and a high response to NO2, even at low concentrations of 100 ppm. The current responses of the SnO2/κ(ε)-Ga2O3:Sn structure to 104 ppm of H2 and 100 ppm of NO2 were 30–47 arb. un. and 3.7 arb. un., correspondingly, at a temperature of 125 °C. The increase in the sensitivity of heterostructures at low temperatures is explained by a rise of the electron concentration and a change of a microrelief of the SnO2 film surface when depositing on κ(ε)-Ga2O3:Sn. The SnO2/κ(ε)-Ga2O3:Sn heterostructures, having high gas sensitivity over a wide operating temperature range, can find application in various fields.

Li3BO3-Li3PO4 Composites for Efficient Buffer Layer of Sulphide-Based All-Solid-State Batteries

All-solid-state batteries (ASSBs) based on sulphide electrolytes are promising next-generation energy storage systems because they are expected to have improved safety, increased volumetric energy density, and a wide operating temperature range. However, side reactions at the cathode/electrolyte interface deteriorate the electrochemical performance and limit the commercialization of ASSBs. Surface coating of the cathode is an efficient approach for overcoming this issue. In this study, new Li3BO3 (LBO)-Li3PO4 (LPO) composites were applied as coating materials for high-Ni cathodes (NCM). PO4-based materials (such as LPO) have been used as coating layers because of their good chemical stability in sulphide electrolytes. However, the ionic conductivity of LPO is slightly insufficient compared to those of generally used ternary oxides. The addition of LBO could compensate for the low ionic conductivity of LPO and may provide better protection against sulphide electrolytes owing to the effect of LBO, which has been used as a good coating material. As expected, the LBO-LPO composites (LBPO) NCM exhibited superior discharge capacity, rate capability, and cyclic performance compared to the pristine and LPO-coated NCMs. X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDS) analyses confirmed that the LBPO coating on the cathodes successfully suppressed the byproduct formation and an undesirable interfacial layer, which are attributed to interfacial side reactions. This result clearly shows the potential of the LBPO coating as an excellent buffer layer to stabilise the oxide cathode/sulphide electrolyte interface.

A flexible, high-energy density, and temperature-tolerant asymmetric supercapacitor based on water-in-salt gel electrolyte

The dramatic development of wearable electronics has led to extensive research into flexible supercapacitors as wearable energy storage devices. The practical application of supercapacitors to wearable electronics requires improved temperature tolerance and high energy density. Herein, we report the fabrication of a high-voltage flexible aqueous supercapacitor featuring high energy density and a wide operating temperature range. This is achieved by the strategy of simultaneously utilizing asymmetric electrodes and water-in-salt gel electrolyte (WISGE). Using NaClO4-based WISGE and asymmetric electrodes consisting of Na-inserted MnO2 and N-doped carbon nanofibers, we obtain excellent electrochemical performance, including a gravimetric capacitance of 97.2 F g−1, energy density of 90 Wh kg−1, power density of 28.1 kW kg−1, operation voltage window of 2.6 V, and capacitance retention of 85.2% over 10,000 charge/discharge cycles. The fabricated flexible supercapacitor is stable under repeated temperature changes between − 20 and 80 °C, regardless of bending deformation. After three cycles of cooling and heating, the initial capacitance at room temperature is 95.1% recovered. This study demonstrates the potential application of our high-performance flexible aqueous supercapacitors to wearable devices, given their resistance to changes in environmental temperature and mechanical deformation.