Maximum Discharge Voltage Research Articles

Flexible Aluminum-Air Battery Based on High-Performance Three-Dimensional Dual-Network PVA/KC/KOH Composite Gel Polymer Electrolyte.

With a large theoretical capacity and high energy density, aluminum-air batteries are a promising energy storage device. However, the rigid structure and liquid electrolyte of a traditional aluminum-air battery limit its application potential in the field of flexible electronics, and the irreversible corrosion of its anode greatly reduces the battery life. To solve the above problems, a PVA/KC/KOH (2 M) composite gel polymer electrolyte (GPE) with a three-dimensional dual-network structure consisting of polyvinyl alcohol (PVA), kappa-carrageenan (KC), and potassium hydroxide was prepared in this paper by a simple two-step method and applied in aluminum-air batteries. At room temperature, the ionic conductivity of the PVA/KC/KOH (2 M) composite GPE was found to be up to 6.50 × 10-3 S cm-1. By utilizing this composite GPE, a single flexible aluminum-air battery was assembled and achieved a maximum discharge voltage of 1.2 V at 5 mA cm-2, with discharge time exceeding 3 h. Moreover, the single flexible aluminum-air battery maintains good electrochemical performance under various deformation modes, and the output voltage of the battery remains at about 99% after 300 cycles. The construction of flexible aluminum-air batteries based on a three-dimensional dual-network PVA/KC/KOH composite GPE provides excellent safety and high-multiplication capabilities for aluminum-air batteries, making them potential candidates for various flexible device applications.

Experimental study on the discharge of a xenon-assisted krypton Hall thruster

The theoretical specific impulse of Hall thrusters using a krypton propellant is much higher than that of those using xenon. However, the actual benefits of this improvement are limited by the difficulty in achieving krypton atom ionization, and its efficiency is much lower than that of xenon. In this study, the anode specific impulse and anode efficiency of Hall thrusters using krypton propellant were improved by adding a small quantity of xenon. A dual-channel supply of xenon and krypton was achieved by optimizing the discharge channel structure based on the design of the aft-loaded magnetic field. The effects of the xenon and krypton supply method and xenon fraction on the discharge characteristics of the Hall thruster were investigated by conducting discharge experiments using the mixed propellant. The results indicated that injecting a small quantity of xenon significantly improved the ionization of krypton, improved the ionization and acceleration efficiency of the thruster, and fully utilized the high specific impulse characteristics of krypton. Furthermore, the addition of a small quantity of xenon also significantly increased the upper limit of the discharge voltage for stable operation using krypton from 500 V. At the maximum tested xenon fraction, the maximum discharge voltage was loaded to 900 V. At a discharge voltage of 800 V, the optimal anode efficiency and anode specific impulse increased by 4.5 % and 534 s, respectively, compared with those for pure xenon propellant (with an anode efficiency of 54 % and anode specific impulse of 3034 s). The results of this study are of great significance for the design of high-efficiency, high-specific-impulse, and low-cost Hall thrusters.

Total neutron emission from deuteron fusion and plasma pinch compression in a medium-sized plasma focus operating with D2 and D2 + Ne gas mixtures—Experimental results

Newly obtained results on hot and dense deuterium and deuterium-neon plasma compression in a z-pinch electrical discharge configuration are presented. The investigated plasma was generated and compressed using 269 high-current discharges in a medium-sized (dense) plasma focus device. The experimental chamber of the device was filled with deuterium and deuterium-neon gas mixtures under constant total mass/density conditions. Magnetic and electric probes, beryllium neutron activation counter, and high-speed four-frame vacuum ultraviolet/soft x-ray pinhole camera were used to study the plasma dynamics and radiation emission. The results obtained experimentally for the first time confirmed clearly a decrease in the minimum radius of plasma columns with an increase in initial neon fraction. Simultaneously, a decrease in the total neutron emission from deuteron fusion was found. The observed plasma/discharge evolution revealed that the classical description of plasma-focus discharges can be approximately correct up to the moment of maximum compression. Including, existence of quasi-equilibrium plasma compression is probable. It is also possible that the homogeneity of plasma columns during the slow compression phase and maximum compression moment increases with the increase in initial neon fraction. The effect of higher stabilization (repeatability) of discharges was confirmed, for higher initial neon fractions. The dependency of the total neutron emission yield on the parameters describing the full discharge dynamics and the maximum discharge voltage was confirmed. The existence of this type of dependency, for a minimum pinch radius is also possible. In contrast, there was little dependency to the total discharge current parameters measured in the collector area.

In Situ Synthesis of AgCl@Ag Plates as Binder-Free Cathodes in a Magnesium Seawater-Activated Battery

A binder-free AgCl@Ag (SPL-A) cathode was prepared via a facile one-step synthesis by the in situ growth of AgCl active material on the surface of Ag foil substrate. Compared with the AgCl cathode (SPL-B) prepared by the traditional smelting-rolling method, the coarse-grained particulates of AgCl in AgCl@Ag cathode facilitated the permeation of the electrolyte. In addition, it exhibited a preferred growth orientation of the (111), (222), and (311) crystal planes to reduce the charge transfer resistance. The electrochemical behaviors of the optimized SPL-A-24 cathode (prepared with reaction time of 24 h) and the SPL-B cathode were also compared. The galvanostatic discharge results showed that SPL-A-24 cathode had a more positive electrode potential than SPL-B cathode (−0.06 V vs −0.19 V at 50 mA cm−2). Moreover, SPL-A cathode exhibited a stable discharge process that SPL-B cathode could not achieve at 100 mA cm−2 and 250 mA cm−2. The magnesium seawater-activated battery assembled with SPL-A-24 cathode displayed a shorter time to reach the voltage plateau (0.2 s), a higher maximum discharge voltage (1.69 V), a larger specific power (255.5 mWh g−1), and higher specific capacity (167.7 mAh g−1) at the discharge current density of 50 mA cm−2.

Design and Construction of Redox Flow Battery using Liquid Extract from Morinda Lucida Leaves

The research is focused on the use of a liquid extract from morinda lucida leaves as electrolyte in the construction of a redox flow battery using fired clay pot as the separating medium. After the Soxhlet extraction, each of the liquid electrolyte was stored in a container for each half-cell, and the electrode was dipped into the electrolyte. For cell testing and charging, a wire was connected to the top of the electrodes. A 3V battery was used to charge the cell, a maximum discharge voltage of 1.31V and a maximum discharge current of 13mA were recorded from the battery testing results. Results showed that the liquid extract from morinda lucida leaves as a good conductor of electricity and a suitable electrolyte for a redox flow battery.

Photo-assisted Al-air batteries based on gel-state electrolyte

The use of new concept electrochemical devices to store and release solar energy has always been a research hotspot in the society of resource shortage. In this work, we firstly introduce sunlight into the Al-air battery by CuO and Cu2O semiconductor electrode materials to improve the discharge voltage under illumination and the calcium alginate hydrogel-based electrolyte is also applied to the Al-air battery. The calcium alginate hydrogel-based electrolyte can greatly inhibit the self-corrosion of aluminum, resulting in the specific capacity of Al-air battery being significantly increased. At the current density of 1 mA cm−2, the CuO air cathode shows better performance, the maximum discharge voltage is 1.37 V and 1.23 V under illumination in aqueous sodium hydroxide solution and hydrogel, respectively, while the maximum discharge is 0.9 V and 0.78 V in the darkness. And the specific capacity in the hydrogel is about 20 times that of the aqueous sodium hydroxide solution. In addition, the semiconductor energy band structure and the discharge mechanism of the photo-assisted Al-air battery under illumination are also studied. This study provides a prospect for the conversion and application of solar energy in the photo-assisted Al-air battery.

Effect of successive plasma shots on the dielectric constant of the CdS:Mn thin films exposed to the helium electron beam of plasma focus device

This paper investigated the emission of plasma concerning electron beam in a low energy Plasma Focus Device. Helium is utilized as a working gas with a pressure of 1.1 Torr. The effects of the voltage, working gas pressure, and parameters of the beam of electron applied were calculated. At the charging voltage of 12 kV, the maximum discharge current is 92kA, the maximum discharge voltage is 2.7 kV, the maximum dI/dt is -37 in.(A.U) and the maximum PMT signal is -4 in.(A.U). To estimate the electron beam energy and calculate the beam current at the side-on location, the Faraday cup was used. Using the electron beam evaporation method with coating unit from Edward 306 Auto under high vacuum conditions at room temperature, CdS1-xMnx (0 ≤ x ≤ 0.1) thin films were successfully deposited on glass substrates. The AC electrical conductivity of the (CdS) and (CdS doped with Mn) are measured. The dielectric constant of the (CdS doped with Mn) reveals that the conduction depends on the frequency. The Ac conductivity (σac) was obtained from the values of ε'. The experimental work and parameters ε' and σac at room temperature were studied as a function of frequency in the range of 100 Hz to 5 MHz. Mechanical studies of the CdS doped with Mn are investigated at different Mn concentrations and different charging voltage.

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster.

Applied-field magnetoplasmadynamic thrusters (AF-MPD thrusters) are hybrid accelerators in which electromagnetic and gas dynamic processes accelerate plasma to high speed; they have considerable potential for future space applications with the significant advantages of high specific impulse and thrust density. In this paper, we present a series of protocols for designing and manufacturing a 100 kW class of AF-MPD thruster with water-cooling structures, a 130 V maximum discharge voltage, a 800 A maximum discharge current, and a 0.25 T maximum strength of magnetic field. A hollow tantalum tungsten cathode acts as the only propellant inlet to inhibit the radial discharge, and it is positioned axially at the rear of the anode in order to relieve anode starvation. A cylindrical divergent copper anode is employed to decrease anode power deposition, where the length has been reduced to decrease the wall-plasma connecting area. Experiments utilized a vacuum system that can achieve a working vacuum of 0.01 Pa for a total propellant mass flow rate lower than 40 mg/s and a target thrust stand. The thruster tests were carried out to measure the effects of the working parameters such as propellant flow rates, the discharge current, and the strength of applied magnetic field on the performance and to allow appropriate analysis. The thruster could be operated continuously for significant periods of time with little erosion on the hollow cathode surface. The maximum power of the thruster is 100 kW, and the performance of this water-cooled configuration is comparable with that of thrusters reported in the literature.

Investigation of Surface Modifications of Metals with Low-Pressure Plasma System

The effects of plasma exposure and impingement of energetic particles are now widely used for substrate cleaning as well as to assist and control thin film growth and various applications. Plasma technology is a versatile green technology used for surface engineering technology. Plasma sources have become a very useful tool for surface modification and deposition of various materials. In this work, typical treatments of the surfaces of Mn, Fe, W and Cu metals were carried out using a low-pressure plasma system with argon gas and operating with an aluminum cathode. The plasma ignition was produced by flowing argon gas between two metal electrodes, and the maximum discharge voltage was 3 kV. All the treated metal samples were exposed to the plasma for a constant time of 2 hours. The modified metal surfaces were characterized by in situ X-ray florescence spectroscopy (XRF), contact angle measurements and scanning electron microscopy (SEM). The wetting behavior of the treated metal surfaces was studied by employing the contact angle method. The contact angle is found to be dependable on the surface layer properties of the metals which in turn is affected by the dose time.

The synthesis of Cu(II), Zn(II), and Co(II) metalloporphyrins and their improvement to the property of Li/SOCl2 battery

One new porphyrin, 5,10,15-triphenyl-20-[4-(2-(4-formoxyl)phenoxy)ethoxy]phenyl porphyrin, and its three corresponding copper(II), cobalt(II), and zinc (II) complexes were synthesized and characterized by IR, UV–vis, 1H NMR, MS, and elementary analysis. Their improvements to the lithium/thionyl chloride (Li/SOCl2) battery were also tested. The results show that the discharge time of Li/SOCl2 battery with porphyrin/metalloporphyrins is approximately 502–692 s longer than that of Li/SOCl2 battery in blank. The maximum initial discharge voltage of battery with the existence of metalloporphyrins is also increased. The energy of Li/SOCl2 battery in blank is 96.3 J while that of Li/SOCl2 battery after adding porphyrin/metalloporphyrins is 153.1 J for metal-free porphyrin, 133.6 J for Cu(II) porphyrin, 167.2 J for Co(II) porphyrin, and 158.3 J for Zn(II) porphyrin, respectively. With increasing battery discharge time by 691.3 s and enhancing maximum discharge voltage by 0.04 V, the Co(II) porphyrin exhibits the best improvement to Li/SOCl2 battery. The results of cyclic voltammetry show that the adding of porphyrins improves the reduction rate of SOCl2.

Hierarchical meso-macroporous LaMnO3 electrode material for rechargeable zinc–air batteries

Cubic-phase LaMnO3 with hierarchical meso-macroporous structures was prepared via a surfactant-templating method with the assistance of Pluronic P-123 surfactant. The sample prepared without the surfactant contained La2O3 and an unknown phase with microparticles, whereas the P-123-assisted samples were nanocrystalline perovskite LaMnO3, with a voluminous and porous microstructure. With the addition of P-123, bimodal macropores interconnected by mesostructured walls can be fabricated. The mesopore size can be regulated by adjusting the P-123 content. The electrochemical performance of the as-prepared LaMnO3 as the cathode electrode for rechargeable zinc–air batteries was evaluated using galvanostatic charge and discharge cycling measurements in a solution of 6M KOH. The sample without surfactant exhibited poor cycling stability and a relatively low discharge voltage of 1.090V, whereas the nanocrystalline and porous LaMnO3 prepared with a P-123/La molar ratio of 10 exhibited excellent cycling stability, with a maximum discharge voltage of 1.158V. The excellent performance of hierarchical meso-macroporous LaMnO3 in terms of stability and discharge voltage might be due to its single phase, large surface area, and high pore volume.

NO conversion by positive streamer discharge—effects of gas compositions and reaction conditions

The effects of gas compositions and reaction conditions on NO conversion by positive streamer discharge were experimentally investigated by using a link tooth wheel-cylinder reactor. The results showed that NO conversion increased with increasing O2 concentration and NH3 concentration, but decreased with increasing inlet NO concentration and gas flow rate. The addition of CO2 or H2O to the feed gas promoted NO conversion by increasing the maximum discharge voltage, and NH4NO3 was formed in the presence of NH3. There was a most suitable range interval between discharge tooth wheels if both NO conversion and energy consumption were considered. Increasing applied voltage resulted in the increase in the amount of O3 generated by streamer discharge.

Masseter muscule activity during the whole day in young adults

This study was conducted to evaluate the biting function during the entire day in young adults by measuring the masseter muscle activity with a 24-hour electromyography (EMG) system. With this system, the masseter muscle activity for 24 hours was recorded in 20 male and 10 female young adult subjects with acceptable occlusion. For the male subjects, means of the number and total duration of bursts over level 2, which is one-fourth of the maximum discharge voltage during maximum clenching, were 1938 times and 357 seconds. For the female subjects, the values were 2356 times and 419 seconds. A large percentage of such high amplitude bursts as level 3 or 4 was observed during meals in both groups. These results indicated that most of the strong bursts of the masseter muscle appeared only during meals and a number of low amplitude bursts were observed during the entire day, although masseter muscle activity during the entire day in young adults was less than expected. It is anticipated that the nature of masticatory muscle activity revealed in this study might provide valuable information about the association between the biting function and the craniofacial structure or malocclusion. (Am J Orthod Dentofac Orthop 1996;110:394-8.)

Discharge stability in E-beam-sustained rare-gas halide lasers

The stability of a glow discharge in rare-gas mixtures containing a small fraction of attaching species is examined, using the e-beam-sustained KrF laser discharge as a generic example. The stability limit is shown to lie near the peak of the voltage-current characteristic, while the mode of instability is dependent on external circuit parameters. The calculated maximum discharge voltage is in good agreement with experimental observation over a wide range of e-beam current densities.