Optimal Voltage Range Research Articles

Microcrystalline-Fe2P4O12 as eco-friendly and efficient anode for high-performance dual-ion battery

Dual-ion batteries (DIBs) have garnered significant interest because of their cost-effectiveness and high level of safety. However, the anode typically utilized tends to show low cyclic stability in complete batteries when the only sources of lithium are primarily consumed in the electrolyte following the development of a solid electrolyte interphase (SEI) during the initial electrochemical process. Here, a simple approach is used to produce microcrystalline carbon-coated Fe2P4O12 at a mild temperature. This material has the ability to store lithium ions, resulting in a specific capacity of 215 mAh/g at a potential range of 1 to 2.5 V vs Li+/Li0. Furthermore, it demonstrates a remarkable coulombic efficiency of 99 % in the initial cycles, even in the absence of a solid electrolyte interphase (SEI) formation. On the other hand, the issue of the high voltage plateau of the graphite cathode is addressed by selecting a total of 4.2 V as the optimal voltage range in DIBs. Simultaneously, the composite Fe2P4O12 also demonstrates exceptional ion diffusion kinetics and reduced interfacial impedance due to its microcrystalline structure. The utilization of the proposed Fe2P4O12 anode addresses a crucial deficiency in the complete range of deep in-situ bioremediation techniques, hence expediting the industrialization process.

Facile Synthesis of Diazaanthraquinone Dimers as High-Capacity Organic Cathode Materials for Rechargeable Lithium Batteries.

Organic cathode materials (OCMs) have tremendous potential to construct sustainable and highly efficient batteries beyond conventional Li-ion batteries. Thereinto, quinone/pyrazine hybrids show significant advantages in material availability, energy density, and cycling stability. Herein, we propose a facile method to synthesize quinone/pyrazine hybrids, i.e., the condensation reaction between ortho-diamine and bromoacetyl groups. Based on it, we have successfully synthesized three 1,4-diazaanthraquinone (DAAQ) dimers, including 2,2'-bi(1,4-diazaanthraquinone) (BDAAQ) with an exceptional theoretical capacity of 512 mAh g-1 based on the eight-electron reaction. It can be fully utilized in Li batteries in a wide voltage range of 0.8-3.8 V, at the cost of inferior cycling stability. In an optimal voltage range of 1.4-3.8 V, BDAAQ exhibits one of the best comprehensive electrochemical performances for small-molecule OCMs, including a high specific capacity of 366 mAh g-1, an average discharge voltage of 2.26 V, as well as a respectable capacity retention of 59% after 500 cycles. Moreover, the in-depth investigations reveal the redox reaction mechanisms based on C═O and C═N groups as well as the capacity fading mechanisms based on dissolution-redeposition behaviors. In brief, this work provides an instructive synthesis method and mechanism understanding of high-performance OCMs based on a quinone/pyrazine hybrid structure.

Enhancing air filtration efficiency with triboelectric nanogenerators in face masks and industrial filters

The removal efficiency of traditional air filters decreases with decreasing particle size, requiring the use of highly compact filter layers to achieve high efficiency, resulting in high-pressure drops and power consumption. To address this issue, this study proposes a novel approach by combining triboelectric nanogenerator (TENG) properties with industrial air filters and face masks to improve removal efficiency while maintaining low-pressure drop. The study investigates the impacts of key parameters, such as airflow velocity, particle size, and applied voltage, on filter performance through a developed mathematical model. The optimal voltage range required to remove specific particle sizes is also modeled, and suitable triboelectric materials for producing the optimal voltage are suggested. Results show that the use of the suggested triboelectric-based filter, generated using a polypropylene (PP)-polyurethane (PU) TENG pair, with a 300 µm filter thickness, 30 µm pore size, and 30 µm fiber diameter, enhances the removal efficiency of particles from 23.0 % to 99.0 %. Specifically, a 10 V voltage on the fiber surface enables the removal of particles in the range of 10 nm to 100 µm with an efficiency of 99.0 %, which is 4 times higher than a traditional filter. The study demonstrates the potential of utilizing various antibacterial and polymer-based triboelectric materials in different applications, including self-powered smart face masks and industrial air filters.

Mechanistic understanding of aging behaviors of critical-material-free Li4Ti5O12//LiNi0.9Mn0.1O2 cells with fluorinated carbonate-based electrolytes for safe energy storage with ultra-long life span

Behind-the-meter storage (BTMS) systems—a viable method to minimize potential risk of blackout events and stabilize the grid—require a different type of cost-effective energy storage with excellent safety, ultra-long (>20 years) cycle life and reasonable energy density compared that of electric vehicles. To increase the energy density and reduce the cost of a long-term cyclable lithium-titanate-based cell, it is required to employ a critical-material-free high voltage cathode and an electrolyte with good electrochemical and transport properties. Here, the long-term electrochemical performance and behaviors of selected critical-material-free Li4Ti5O12 (LTO)//LiNi0.9Mn0.1O2 (LNMO) full cells for BTMS applications are evaluated and analyzed in the optimized voltage range of 1.4–2.7 V at 45 °C with different fluorinated carbonate-based electrolytes. The fluoroethylene carbonate (FEC)-based electrolyte cell shows the highest capacity retention of 57.9 % and Coulombic efficiency (CE) of 99.96 % after 1000 cycles, potentially attributed to a dense, homogenous and less resistive LiF-rich solid-electrolyte interphase (SEI) layer formed on the surface of LTO that may mitigate electrolyte decomposition and maintain relatively low cell impedance during cycling. The 3,3,3-fluoroethylmethyl carbonate (F-EMC)-based electrolyte cell, however, presents the worst performance with lower capacity and a sharp decrease of CE, due to unstable and non-uniform SEI formation and continuous oxidative electrolyte decomposition. This mechanistic understanding of cell aging behaviors and failure mechanisms with detailed analysis of surface chemistry and electrode morphology can guide design of new electrode chemistries and electrolyte formulations for the development of BTMS batteries.

Preparation of an electrochemical biosensor based on indium tin oxide and its performance in detecting antibiotic resistance genes

In this study, an antibiotic resistance genes (ARGs) detection biosensor was successfully fabricated by assembling the hairpin DNA probe on an indium tin oxide (ITO) electrode deposited with gold nanoparticles. Three methods of potentiostatic, galvanostatic and cyclic voltammetric for deposition were compared, and the cyclic voltammetric was proved to be the most effective one. The optimal voltage range for it was −0.9 to −0.2 V with 40 cycles, which can deposit uniform and dense nano-gold film on the ITO electrode. In addition, DNA with mismatched bases was applied to study the specificity of the sensor. Results of DPV showed that the current significantly reduced to 281.0 μA only when the biosensor was hybridized with completely complementary DNA. What’s more, there was a strong correlation between the concentration of ARGs and electrochemical signal. The correlation coefficient reached 0.987, and the detection limit was 30.0 pg/μl, which met the demand for monitoring ARGs in the water environment. All in all, the biosensor prepared in this study possesses satisfactory specificity and sensitivity, which is beneficial for practical application.

A new interpretation of nonpulmonary vein substrates of the left atrium in patients with atrial fibrillation.

BackgroundSubstrate analysis of the left atrium in patients undergoing atrial fibrillation ablation has limitations when performed by means of simple bipolar acquisition.ObjectiveTo evaluate the incidence of low‐voltage zones (LVZs) through maps constructed by means of various catheters: multipolar (MC), omnipolar (OC), and circular catheters (CMCs) with the 3D electro‐anatomical systems (3d‐S) CARTO3 and EnSite Precision.MethodsTo assess LVZs, we acquired maps by means of CMC and MC in the voltage range 0.05‐0.5 mV in 70 consecutive patients in sinus rhythm. In the case of OC only, we made an intra‐patient comparison of bipolar maps constructed by means of the along and across, and HD‐Wave configurations of the EnSite 3d‐S in the ranges of 0.05‐0.5 and 0.5‐1.0 mV. On the basis of this comparison, we chose the range that best identified LVZs as a set of different colors (SDC) compatible with patchy fibrosis (qualitative analysis). Subsequently, we detected the voltage values corresponding to purple and gray points, close to SDC, and the value inside corresponding to blue, green, and red colors, and we evaluated the color change in other voltage ranges. Finally, we performed a quantitative analysis of LVZs by applying the qualitative characteristics described above.ResultsOn the basis of our settings, for OC, the optimal range identifying LVZs was 0.3‐0.6 mV. OC revealed smaller LVZs than MC (P < .05 or P < .001), except in the lateral wall. No significant differences were observed between CMCs.ConclusionsIn our experience, OC does not present the limits of bipolar HD maps, though further studies are needed in order to confirm that 0.3‐0.6 mV is the optimal voltage range within which to identify LVZs.

Dendrite-structured FeF2 consisting of closely linked nanoparticles as cathode for high-performance lithium-ion capacitors

Abstract Lithium-ion capacitors (LICs) are regarded as a good choice for next-generation energy storage devices, which are expected to exhibit high energy densities, high power densities, and ultra-long cycling stability. Nevertheless, only a few battery-type cathode materials with limited kinetic properties can be employed in LICs, and their electrochemical properties need to be optimized urgently. Here, we exploit a new dendrite-structured FeF2 consisting of closely linked primary nanoparticles using a facile solvothermal method combined with the subsequent annealing treatment. This particular architecture has favorable transport pathways for both lithium ions and electrons and exhibits an ultrafast charge-discharge capability with high reversible capacities. Furthermore, a well-designed LIC employing the prepared dendrite-structured FeF2 as the battery-type cathode and commercialized activated carbon (AC) as supercapacitor-type anode was constructed in an organic electrolyte containing Li ions. The LIC operates at an optimal voltage range of 1.1–3.8 V and shows a maximum high energy density of 152 W h kg−1 and a high power density of 4900 W kg−1 based on the total mass of cathode and anode. Long-term cycling stability (85% capacity retention after 2000 cycles) was achieved at 1 A g−1. This work suggests that the dendrite-structured FeF2 is a prime candidate for high-performance LICs and accelerates the development of hybrid ion capacitor devices.

MoS2 hollow spheres in ether-based electrolyte for high performance sodium ion battery

In this work, instead of coupling with carbon-based materials, the obtained MoS2 hollow spheres constructed of many curved nanosheets have been successfully fabricated via one-pot hydrothermal process. Meanwhile, inheriting the advantages of hollow structure and combining the merits of ether-based electrolyte with the optimized voltage range, the obtained MoS2 electrode can demonstrate excellent electrochemical performance which deliver a large capacity, superior rate (391.4 mA h g−1 at 0.1 A g−1 and 347.3 mA h g−1 at 0.5 A g−1) and long cycling performance (334.6 mA h g−1 at 2 A g−1 after 1200 cycles) when employed as anode material for sodium ion battery.

Surface engineering induced core-shell Prussian blue@polyaniline nanocubes as a high-rate and long-life sodium-ion battery cathode

Surface engineering is highly desirable but still challenging for developing high-rate and long-term life energy storage materials. Herein, Prussian blue@polyaniline nanocube is synthesized by an aqueous precipitation method and the following polymerization process of aniline. Benefiting from the coordinating role of polyvinyl pyrrolidone between Prussian blue and polyaniline, Prussian blue@polyaniline nanocube presents a core-shell structure with a diameter of about 600 nm and the uniform polyaniline coating layer is averagely 20 nm in thickness. The incorporation of polyaniline on Prussian blue is efficient to enhance the electrical conductivity and the kinetics of Na+ transmission during cycling, leading to the higher specific capacity and better rate performance. The sodium storage properties of the cathode are also investigated in different voltage ranges. Owing to the core-shell structure and the optimized voltage range, Prussian blue@polyaniline electrode delivers a specific capacity of 108.3 mAh g−1 at 100 mA g−1 with a capacity retention of 93.4% after 500 cycles and maintains a considerable specific capacity of 90.3 mAh g−1 even at 2 A g−1 in the voltage range of 2.0–3.6 V. The strategy of polyvinyl pyrrolidone assisted polymerization of polyaniline layer on Prussian blue nanoparticles can be extended to surface modification for other electrode materials.

Mesoporous Hollow Sb/ZnS@C Core–Shell Heterostructures as Anodes for High‐Performance Sodium‐Ion Batteries

Combining the advantage of metal, metal sulfide, and carbon, mesoporous hollow core-shell Sb/ZnS@C hybrid heterostructures composed of Sb/ZnS inner core and carbon outer shell are rationally designed based on a robust template of ZnS nanosphere, as anodes for high-performance sodium-ion batteries (SIBs). A partial cation exchange reaction based on the solubility difference between Sb2 S3 and ZnS can transform mesoporous ZnS to Sb2 S3 /ZnS heterostructure. To get a stable structure, a thin contiguous resorcinol-formaldehyde (RF) layer is introduced on the surface of Sb2 S3 /ZnS heterostructure. The effectively protective carbon layer from RF can be designed as the reducing agent to convert Sb2 S3 to metallic Sb to obtain core-shell Sb/ZnS@C hybrid heterostructures. Simultaneously, the carbon outer shell is beneficial to the charge transfer kinetics, and can maintain the structure stability during the repeated sodiation/desodiation process. Owing to its unique stable architecture and synergistic effects between the components, the core-shell porous Sb/ZnS@C hybrid heterostructure SIB anode shows a high reversible capacity, good rate capability, and excellent cycling stability by turning the optimized voltage range. This novel strategy to prepare carbon-layer-protected metal/metal sulfide core-shell heterostructure can be further extended to design other novel nanostructured systems for high-performance energy storage devices.

Separation of large DNA molecules by size exclusion chromatography-based microchip with on-chip concentration structure

The separation of DNA molecules according to their size represents a fundamental bioanalytical procedure. Here, we report the development of a chip-sized device, consisting of micrometer-sized fence structures fabricated in a microchannel, for the separation of large DNA molecules (over 10 kbp) based on the principle of size exclusion chromatography (SEC). In order to achieve separation, two approaches were utilized: first, the DNA samples were concentrated immediately prior to separation using nanoslit structures, with the aim of improving the resolution. Second, a theoretical model of SEC-based separation was established and applied in order to predict the optimal voltage range for separation. In this study, we achieved separation of λ DNA (48.5 kbp) and T4 DNA (166 kbp) using the present SEC-based microchip.

High performance Na3V2 (PO4)3/C composite electrode for sodium-ion capacitors

Sodium-ion capacitors were assembled with Na3V2(PO4)3/C composite cathode and activated carbon (AC) anode. In this work, Na3V2(PO4)3 (NVP) and NVP/C have been investigated as electrode materials in sodium ion capacitors for the first time. Electrochemical tests, such as cyclic voltammetry (CV), chronopotentiometry, and cycling were also performed to study the behavior of NVP and NVP/C. The specific capacitance and energy density of NVP/C composite electrode are as high as 51.0 F g−1 and 15.9 Wh kg−1. The optimized voltage range of sodium-ion capacitors is from 0 to 1.5 V. NVP/C composite demonstrates that it retained up to 80 % of the initial capacitance after 100 cycles. The outperforming results could be ascribed to the NVP/C composite, which indicates that NVP/C composite is more suitable as cathodematerials for sodium-ion capacitors.

The Influence of Parameters of Microarc Oxidation on the Surface Roughness and Wettability of Calciumphosphate Coatings

The influence of the voltage of micro-arc oxidation on the physicochemical properties of the calciumphosphate coatings has been investigated. The linear growth of the roughness and hyperbolic decrease of the surface energy with growth of the oxidation voltage have been revealed. It was shown that the calciumphosphate coatings have low contact angle and high surface energy and, as a consequence, are hydrophilic. The optimal voltage range of the oxidation has been found. It varies from 200 to 250 V. This range provides the coating formation with the following specified parameters: surface roughness of 2 – 3.5 µm; contact angles with water and glycerol of 18 - 25º and 35 - 45º, respectively, and free surface energy of 73 - 80 mN/m.

Voltage-assisted polymer wafer bonding

Polymer wafer bonding is a widely used process for fabrication of microfluidic devices. However, best practices for polymer bonds do not achieve sufficient bond strength for many applications. By applying a voltage to a polymer bond in a process called voltage-assisted bonding, bond strength is shown to improve dramatically for two polymers (Cytop™ and poly(methyl methacrylate)). Several experiments were performed to provide a starting point for further exploration of this technique. An optimal voltage range is experimentally observed with a reduction in bonding strength at higher voltages. Additionally, voltage-assisted bonding is shown to reduce void diameter due to bond defects. An electrostatic force model is proposed to explain the improved bond characteristics. This process can be used to improve bond strength for most polymers.

Abnormal bipolar-like resistance change behavior induced by symmetric electroforming inPt/TiO2/Pt resistive switching cells

Abnormal bipolar-like resistive changes are reported inTiO2 thin films sandwiched between Pt top and bottom electrodes. The abnormal behavior isshown relying on the applied voltage range. That is, normal bipolar switching is also shownin the same sample with the optimized voltage range. In the abnormal mode, both set- andreset-like changes in resistance take place under the same polarity of the applied voltage.This abnormal behavior is considered to be due to symmetric electroforming which isassumed to activate electrochemical reactions involving oxygen vacancies at bothPt/TiO2 interfaces. We analyze the abnormal behavior in terms of the interfacial resistive switchingtaking place on both interfaces nearly simultaneously.

Optimizing the nematic liquid crystal relaxation speed by magnetic field

Nematic liquid crystalline materials have been widely used in electro-optical control of visible light. However, when IR light is considered, the thickness of the liquid crystal layer must be increased which causes the relaxation time of the material to be slower than required for many applications. In this paper we use a magnetic field to increase the speed of thick nematic devices. We show that above a particular magnetic field strength, thicker cells relax more quickly than thinner ones. Also, we find that there exists an optimal voltage range for devices of a particular thickness and with a particular applied magnetic field. Devices that allow a half-wave modulation of 1.55μm light in less than 5ms are shown to be possible with the use of a 2T magnetic field.

Electro-Fenton 반응을 이용한 유독성 유기화합물 처리

The feasibility and efficiency of the hydrogen peroxide produced by an electrolysis cell reactor was investigated, From regulating voltages for the given reaction time, the concentration of the hydrogen peroxide was gradually increased with increasing voltages. Optimal voltage range was found to be 10～15 V. The concentration of hydrogen peroxide was much higher with oxygen gas than without oxygen gas in the cathodic chamber. But there was a little difference in the generating rate of hydrogen peroxide regardless of the presence of nitrogen gas. Under given conditions, the maximum value of ICE(Instantaneous Current Efficiency) was about 38%, and then current density was 74 <TEX>$mA/\textrm{cm}^2.$</TEX> The specific energy consumption was <TEX>$0.694[kWh/kg-H_2O_2].$</TEX> Since Esp (Specific Energy Consumption)was very little value, It did not demand high energy in this system. Using the hydrogen peroxide gained in the experiment, Fenton's reaction was conducted and the removal of nitrobenzene, 3-chlorophenol and dye wastewater was studied. This results were very similar to the Fenton's reaction by using commercial hydrogen peroxide.