Low-voltage Discharge Research Articles

CoPSe: A New Ternary Anode Material for Stable and High‐Rate Sodium/Potassium‐Ion Batteries

The exploration of ideal electrode materials overcoming the critical problems of large electrode volume changes and sluggish redox kinetics induced by large ionic radius of Na+ /K+ ions is highly desirable for sodium/potassium-ion batteries (SIBs/PIBs) toward large-scale applications. The present work demonstrates that single-phase ternary cobalt phosphoselenide (CoPSe) in the form of nanoparticles embedded in a layered metal-organic framework (MOF)-derived N-doped carbon matrix (CoPSe/NC) represents an ultrastable and high-rate anode material for SIBs/PIBs. The CoPSe/NC is fabricated by using the MOF as both a template and precursor, coupled with in situ synchronous phosphorization/selenization reactions. The CoPSe anode holds a set of intrinsic merits such as lower mechanical stress, enhanced reaction kinetics, as well as higher theoretical capacity and lower discharge voltage relative to its counterpart of CoSe2 , and suppressed shuttle effect with higher intrinsic electrical conductivity relative to CoPS. The involved mechanisms are evidenced by substantial characterizations and density functional theory (DFT) calculations. Consequently, the CoPSe/NC anode shows an outstanding long-cycle stability and rate performance for SIBs and PIBs. Moreover, the CoPSe/NC-based Na-ion full cell can achieve a higher energy density of 274Wh kg-1 , surpassing that based on CoSe2 /NC and most state-of-the-art Na-ion full cells based on P-, Se-, or S-containing binary/ternary anodes to date.

The role of O2 in O-redox cathodes for Li-ion batteries

The energy density of Li-ion batteries can be improved by storing charge at high voltages through the oxidation of oxide ions in the cathode material. However, oxidation of O2− triggers irreversible structural rearrangements in the bulk and an associated loss of the high voltage plateau, which is replaced by a lower discharge voltage, and a loss of O2 accompanied by densification at the surface. Here we consider various models for oxygen redox that are proposed in the literature and then describe a single unified model involving O2− oxidation to form O2, most of which is trapped in the bulk and the remainder of which evolves from the surface. The model extends the O2 formation and evolution at the surface, which is well known and well characterized, into the electrode particle bulk as caged O2 that can be reversibly reduced and oxidized. This converged understanding enables us to propose practical strategies to avoid oxygen-redox-induced instability and provide potential routes towards more reversible, high energy density Li-ion cathodes.

Mechanism and Transformation Directions of 1,1,2 - trichloroethane in the Liquid Phase by Low-voltage Electrical Discharges

1,1,2-trichloroethane is transformed by the action of low-voltage (60 V DC) pulse discharge in the liquid medium in the nanostructure, cis-ClCH = CHCl, trans-ClCH = CHCl, CH2 = CCl2 and HCl. Conversion 1,1,2-trichloroethane 21 wt%, hydrogen chloride yield was 88.4 wt%, yield solid phase 11.6 wt%. The morphology and composition of solid phase products have been determined. According to energy dispersive X-ray spectroscopy, solid-phase products have an elemental composition, % atom: carbon — 90.5-94.2, chlorine — 1.35.4, oxygen — 3.1-4.5. The structures of 1,1-dichloroethylene and cis-, trans-1,2-dichloroethylene, as well as the isomer ratios were determined by 1H NMR. The relative content of isomers: cis-1,2-dichlorethylene 44%, trans-1,2-dichlorethylene 34%, 1,1-dichloroethylene 22%. Quantum-chemical modeling revealed the mechanism of formation of the obtained dichlorethylenes. According to the calculation results, 1,1,2-TCA is involved in the reaction in the triplet state. The difference in energy between the ground and excited states is 66.2 kcal/mol. The elimination of HCl is carried out by an activated chlorine atom generated during the transfer of 1,1,2-TCA under the action of electric discharges from the singlet state to the triplet state.

Fragmentation of Toluene by Non-Thermal Plasmas in Liquids

The influence of the energy of low-voltage discharges in the liquid phase on the directions of fragmentation of toluene is studied. The discharges were generated by a 60 V DC source with a capacitor of 90 μF, 20090 μF, and 40090 μF. Fragmentation of toluene leads to the formation of carbon structures on the surface of graphite electrodes and in a liquid medium. It was revealed that an increase in the power of electric discharges leads to the growth of carbon structures on the surface of electrodes, reduces the output of the gas phase and finely dispersed carbon structures. The morphology and composition of solid phase products were determined by scanning electron microscopy and energy dispersive X-ray spectroscopy. Nanosized carbon structures are obtained in the form of aggregates - carbon nanohorns, which actively adsorb oxygen (content 0.9-3.6 at%). The composition of gaseous products was determined by gas chromatography. It was revealed that with an increase in the power of electric discharges, the hydrogen content slightly increases from 74.8 to 75.15 mol%, methane from 5.86 to 6.55 mol%, neopentane from 0.02 to 0.55 mol%. At the same time, the acetylene content in gaseous products decreases from 18.14 to 16.36 mol%.

Diffusion charging of nanometer-sized liquid aerosol particles

Aerosol particles play an important role in atmospheric physical or chemical reactions. Charging of aerosol particles is also widely used in various engineering applications, such as electrical low-pressure impactors and differential mobility analyzers. In this paper, the charging process of nanometer-sized liquid aerosol particles in an atmospheric environment is studied theoretically and experimentally. The traditional charging equation is modified taking the variation of carried charges and the number density of liquid aerosol particles into consideration, due to the coalescence of liquid aerosol particles that brings 100% charge conversion efficiency. By fitting the experimental data under a low discharge voltage, an appropriate combination (r, η) is selected, where r is a specific droplet radius and η is the corresponding equivalent conversion factor of charges. The results from the fitting combination (r, η) are in good agreement with the experimental data and it further demonstrates that the charging evolution of droplets with various radiuses under various voltages can be derived from the existing experimental data under a low voltage. In addition, the concept of a charging time constant τ 0.1 is introduced to describe the charging rate. This paper may provide a reference to reveal and optimize the charging process of liquid aerosol particles and broaden the engineering applications for the charging of aerosol particles.

Influence of low-voltage discharge energy on the morphology of carbon nanostructures in induced benzene transformation.

The directions of the transformation of benzene induced by low-voltage discharges at various energies of pulsed discharges were revealed. This paper shows the dependencies of the morphology and other characteristics of nanostructures obtained in the induced transformation of benzene on the energy of pulsed discharges. Nanostructures with different morphologies are formed when the energy of the low-voltage discharges changes during the induced transformation of benzene in the liquid phase. Two types of carbon nanostructures were formed in the induced destruction of benzene with a 90 μF capacitor. The first type of structure includes graphite fibers, two- and three-layer graphene sheets, as well as two- and three-layer hollow spheres and microstructures in the form of CNHs. The microstructures of the second type were onion-like spheroids. An increase in the capacitance up to 20 090 μF led to the formation of two types of nanostructures: onion-like spheroids and carbon fibers. A further increase in the capacitance to 40 090 μF caused the formation of onion-like spheroids.

Organization of the cephalic lateral-line canals in Electrophorus varii de Santana, Wosiacki, Crampton, Sabaj, Dillman, Mendes-Júnior & Castro e Castro, 2019 (Gymnotiformes: Gymnotidae)

Abstract Electrophorus spp. generate high-voltage electric discharges for defense and hunting, and low-voltage electric discharges (as other Gymnotiformes) for electrolocation and communication. Despite intense interest in the unusual electrogenic and electroreceptive capacities of electric eels, the other sensory systems of Electrophorus spp. are relatively poorly known. Here we describe the ontogenetic development and organization of the cephalic lateral-line canals in the lowland electric eel, Electrophorus varii. Preserved specimens of larvae, juveniles, and adults were examined to describe the spatial distribution of the canals and pores. Ontogenetic shifts of the cephalic lateral line formation were observed for each canal and support a hypothesis of non-synchronized development. The morphogenesis of cephalic canals in larvae and juveniles begins just before the onset of exogenous feeding. In adults, the cephalic sensory canals are formed separately from the skull and overlay cranial and mandibular bones and muscles. This study provides the first detailed description of the development and organization of the cephalic lateral-line system in Electrophorus varii.

Control and analysis of epilepsy waveforms in a disinhibition model of cortex network

Considering the disinhibition circuit between inhibitory neuronal populations with different time scales in cortical neural networks, here we propose a novel model to describe the occurrences and transitions of epilepsy waveforms. With the model we can successfully simulate poly-spike complexes, which are common in electrophysiological experiments and focal epilepsy patients. Meanwhile, we focus on the dynamic transitions between epilepsy waveforms and normal state and are devoted to exploring effective electrical stimulation strategies. Results show that disinhibition can induce an epileptic bidirectional transition, which is from spike and wave discharges, to poly-spike complexes and then to low-voltage rapid discharge activity, or it is reversed. And fascinating dynamical transition behaviors can be induced by varying average inhibitory synaptic gain. Interestingly, after applying two different control signals (deep brain stimulation and oscillatory input) to the system, all epilepsy waveforms can be suppressed or even eliminated. Results shed light on the pathophysiological mechanisms of epilepsy and guide clinical treatment from a theoretical viewpoint.

Плазма тлеющего разряда с протяженным полым катодом

A low-voltage low-pressure glow discharge with a hollow cathode is considered. The discharge is ignited in a reflective discharge system with two symmetrical peripheral discharge chambers, with a common extended hollow cathode at forevacuum. Plasma parameters were determined, admissible diameter of the plasma column in a hollow cathode. It is shown that there is no electric double layer in the region of the output aperture of the cathode cavity.

The Transformation of Di- and Tri-chloromethane Induced By Low Voltage Discharge


 
 
 This article is focused on the transformation of di- and trichloromethane by induced low-voltage discharges in the liquid phase. To generate discharges, a direct current source is used (capacitance 2200 μF, voltage 60 V). The products and probable intermediates of the CH2Cl2 and CHCl3 transformation were determined by the methods of thermodynamic modeling, FTIR spectroscopy and electron microscopy. Under the action of low-voltage discharges on the liquid substrates, needle fullerene- like structures are formed. In this case the gas phase consists mainly of hydrogen chloride. From the simulation of the nonequilibrium composition of particles and molecular systems it follows that in the course of induced reactions of CH2Cl2 and CHCl3 and geminal elimination of HCl molecules, predominantly carbene-type intermediates are generated.
 
 
 
 Keywords: dichloromethane, trichloromethane, low temperature plasma, discharges in the liquid phase
 
 
 
 
 

Nano SnO2 and Sb2O3 combined with CNTs as a high-capacity lithium storage material

The combination of Sb2O3 or SnO2 with graphene has become a research hotpot in recent years. However, several problems, namely the loading of the active materials, space utilization in composites, and the intrinsic volume expansion of Sb2O3 and SnO2, have yet to be fully resolved. To overcome these disadvantages, in this work Sb2O3/carbon nanotubes (CNTs)/SnO2 composite have been synthesized, in which the CNTs act as a network to ensure the electronic conductivity and buffer of the volume expansion. The SnO2 nanoparticles are aligned by the CNTs and Sb2O3 is dispersed in the voids between them. Space utilization and the loading of the oxides are thereby maximized. Moreover, the resultant composite retains small amount of water or alcohol, which does not affect the cyclic stability, but may have increased the ionic and electronic conductivity, improving the electrochemical performance. A discharge capacity of 910 mAh g−1 after 250 cycles at 100 mA g−1 is realized for Sb2O3/CNT/SnO2. Moreover, the contribution of the pseudocapacitance to the rate discharge capability is obvious, which arises from the different heterointerfaces between Sb2O3/CNTs, CNTs/SnO2 or Sb2O3/SnO2. The homogenous distribution of Sn and Sb in CNTs after cycling leads to a lower discharge voltage, improving the application prospects. Although some collapse and cracks are detected, the CNTs network connects the oxides, ensuring the structural stability and the cyclic stability of Sb2O3/CNT/SnO2. This strategy represents a new concept for the design of multi-component materials for lithium storage.

Влияние вида функции распределения электронов в плазме и дисперсии по энергии электронного пучка на устойчивость низковольтного пучкового разряда

Within the framework of the kinetic approach, the conditions for the loss of stability of a low-voltage beam discharge in inert gases (LVBD) are studied depending on the temperature of the electron beam, the dispersion of the electron beam velocity in the direction of the discharge axis, and the form of the electron energy distribution function (EEDF). Regimes are considered when the interelectrode distance is on the order of the electron mean free path relative to elastic collisions with inert gas atoms. It is shown that the beam temperature Tb, determined in the LVBD by the cathode temperature not exceeding 1500 K, and the dispersion of the beam electron energy, which in the LVBD can be significantly higher than kTb and reaches 1 - 2 eV, have little effect on the conditions for the loss of stability of the LVBD and the magnitude of the growth rate of disturbance amplification at frequencies up to plasma It was found that the form of the EEDF monotonically decreasing with increasing electron energy also does not affect the parameters of the perturbations propagating in the LVBD at the beam energy much higher than the average electron energy in the plasma. The results obtained are applicable not only to LVBD, but also to other types of self-sustained beam discharges.

Low-Power Electric Discharges with Metallic, Dielectric, and Electrolytic Electrodes at Low Frequencies and Atmospheric Pressure

The results of experimental studies of an electric discharge and a low-power dielectric barrier discharge between metallic and electrolytic electrodes at low frequencies of 20, 33, and 100 Hz are presented. The burning of a low-voltage anomalous discharge of alternating current at atmospheric pressure with an increasing volt-ampere characteristic was recorded. Images of the discharge and current-voltage characteristics of electric and dielectric barrier discharges with metallic (pin and plate) and liquid (industrial water) electrodes are presented. Features of the burning of electric and dielectric barrier discharges of low-frequency current with liquid electrodes and metallic electrodes of various shapes are revealed.

Role of plasma parameters on the characteristics properties of flexible transparent ITO films deposited by 3D facing and planar facing magnetron sources

A rectangular closed and hollow three-dimensionally confined large area magnetron source (3-DCLAMS) and a conventional moderate area facing target magnetron source (FTMS) have been used to study the plasma characteristics using different diagnostics at different working pressures. Flexible indium tin oxide (ITO) films deposited at similar operating conditions using these sources were characterized by numerous standard analyses to study their film properties. The 3-DCLAMS with high discharge current at a low-discharge voltage is capable of generating high plasma density, which assists a high ion flux and energy density on the substrate that is necessary for the high growth rate deposition of highly conductive crystalline ITO films with smooth surface morphology. Utilizing suitable plasma characteristics, highly conductive and transparent ITO films of 30 nm with the minimum resistivity ρ ∼ 4.1 × 10−4 Ω cm and ∼9.3 × 10−4 Ω cm and average transmittance T ∼ 84% and 82%, respectively, were deposited in the 3-DCLAMS and the FTMS system. The presented result shows that the 3-DCLAMS system could be useful for making high-quality, flexible ITO films at a very high deposition rate of ∼250 nm/min.

Architecting a Stable High-Energy Aqueous Al-Ion Battery.

Aqueous Al-ion batteries (AAIBs) are the subject of great interest due to the inherent safety and high theoretical capacity of aluminum. The high abundancy and easy accessibility of aluminum raw materials further make AAIBs appealing for grid-scale energy storage. However, the passivating oxide film formation and hydrogen side reactions at the aluminum anode as well as limited availability of the cathode lead to low discharge voltage and poor cycling stability. Here, we proposed a new AAIB system consisting of an AlxMnO2 cathode, a zinc substrate-supported Zn-Al alloy anode, and an Al(OTF)3 aqueous electrolyte. Through the in situ electrochemical activation of MnO, the cathode was synthesized to incorporate a two-electron reaction, thus enabling its high theoretical capacity. The anode was realized by a simple deposition process of Al3+ onto Zn foil substrate. The featured alloy interface layer can effectively alleviate the passivation and suppress the dendrite growth, ensuring ultralong-term stable aluminum stripping/plating. The architected cell delivers a record-high discharge voltage plateau near 1.6 V and specific capacity of 460 mAh g-1 for over 80 cycles. This work provides new opportunities for the development of high-performance and low-cost AAIBs for practical applications.

Advanced ordered mesoporous carbon with fast Li-ion diffusion for lithium–selenium sulfide batteries in a carbonate-based electrolyte

Lithium-selenium sulfide (Li–SeS2) batteries are promising next-generation batteries due to their high energy density (1124 mAh g−1 and 3372 mAh cm−3). In a carbonate-based electrolyte, Li–SeS2 batteries show excellent cycle life but low discharge voltage. This low discharge voltage is affected by the SeS2 content in the composite. To increase the energy density, both the discharge voltage and SeS2 content should be elevated simultaneously. Herein, various structures of ordered mesoporous carbons (OMCs) are investigated to overcome the low discharge voltage while containing a high SeS2 content. By tuning the OMC structure with a large pore volume and effective morphology, Li-ion diffusion is improved, thus leading to decreased ohmic resistance and charge-transfer resistance. Even at a high SeS2 content of 75 wt.%, a platelet-type OMC (POMC2.0) with a pore volume of 2.0 cm3 g−1 enables operation at 2.0 V in a carbonate-based electrolyte. The Li–SeS2 batteries show excellent cycle performance with an average capacity of 552 mAh g−1 for 1600 cycles in a carbonate-based electrolyte.

Simultaneous generation of several waves in a rare gas low-voltage beam discharge

The instability of a low-voltage beam discharge in rare gases is studied using He as an example. Attenuation of an electron beam due to collisions of electrons with atoms is taken into account when the electron mean free path is of the order of the inter-electrode distance. It was found that amplification of several waves with different increments and different speeds is possible with the loss of stability. In the case of a linear decrease in the beam intensity, two waves are generated. The wave having a smaller gain increment propagates at a higher speed. The indicated phenomenon is characteristic not only for a low-voltage beam discharge in rare gases, but also for any “cold high-energy electron beam—plasma” system when collisions of beam electrons with atoms should be taken into account.

Ignition characteristics of energetic nichrome bridge initiator based on Al/CuO reactive multilayer films under capacitor discharge and constant current conditions

Four types of Al/CuO energetic nichrome bridges (ENCBs) initiators are reported, prepared by integrating Al/CuO reactive multilayer films (RMFs) on different V-shaped nichrome bridges (NCBs) through magnetron sputtering technology. V-type angles of NCBs are 150°, 136°, 120° and 90°. The fabrication, electrical explosive characteristics of these ENCBs initiators under capacitor discharge, as well as its firing process under constant current conditions are systematically described. The results reveal a ‘stagflation’ phenomenon in high-speed photograph of ENCBs at low discharge voltage, which is consistent with the result of optical microscope images. It is noted the electric explosion delay time decreases with an increase in the discharged voltages, while the critical ignition energy has no relationship with discharged voltages. Moreover, among the four ENCBs, the one with V-angle of 90° exhibits the shortest electric explosion delay time and lowest critical burst energy. This suggests that the electrical explosion performance of ESCBs can be adjusted by optimising the V-shaped angle and the discharge voltage. At last, the high combustion efficiency of ENCB is proved by comparative test with NCB at 0.6 A. And ENCBs have better heating efficiency than nichrome wire with the same resistance at 0.4A and 0.6A.

Effect of a single air bubble on the collapse direction and collapse noise of a cavitation bubble

Studying the influence of a single air bubble on the noise intensity of cavitation bubble collapse has great significance for understanding the mechanism of air entrainment to alleviate cavitation in hydraulic engineering. A cavitation bubble is generated by an underwater low-voltage electric discharge device and interacts with a rising air bubble. Only the cases where the cavitation bubble centroid, air bubble centroid, and hydrophone probes are located approximately on the same horizontal line are analyzed. The results show that the roundness, size and distance of an air bubble have a very important effect on the collapse direction and collapse sound pressure of the cavitation bubble. The findings also reveal that the direction of collapse is closely related to the collapse sound pressure, while the dimensionless distance γ and dimensionless radius roundness ratio ε’ are important parameters that determine the collapse direction of the cavitation bubble.

Fabrication and charge–discharge properties of composites of LiF and NixMn1−xO solid solution for cathode material of Li-ion secondary battery

LiF–NixMn1−xO composites are prepared by the mechanical milling of LiF and NixMn1−xO (x ≤ 1) solid solution for 72 h. The obtained composites are examined by XRD, charge–discharge measurements, CV, and XPS. X-ray diffraction peaks of LiF–NixMn1−xO are broadened by milling. The diffraction peaks of NixMn1−xO in x < 0.5 are shifted to the higher angle by milling together with LiF. The discharge capacity and voltage of the LiF–NixMn1−xO composites changes with the molar ratio of NiO and MnO. The composite containing a large amount of Mn showed a lower discharge voltage and a larger discharge capacity. The composites containing a large amount of Ni show higher discharge voltage. The maximum discharge capacity among LiF–NixMn1−xO composites is obtained at x = 0.2, and its value is 279 mAh g−1 for cut-off voltages of 2.0–4.8 V at 0.1 C. The XPS measurement shows that the Mn2+ and Ni2+ ions are oxidized to Mn3+ and Ni3+ions in charging process and are reduced to Mn2+ and Ni2+ ions in the discharging. The oxidation and reduction process between Mn2+ and Mn3+ greatly contribute in the charge and discharge process of LiF–Ni0.5Mn0.5O composite. Discharge capacity of composite of LiF and Ni0.2Mn0.8O is 279 mAh g−1.