Charge-discharge Characteristics Research Articles

Three-dimensional entangled and twisted structures of nitrogen doped poly-(1,4-diethynylbenzene) chain combined with cobalt single atom as a highly efficient bifunctional electrocatalyst

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) have been explored extensively for various energy conversion and storage system. Development of metal single atom doped well designed carbon substrates are considered as a new effective strategy to enhance catalytic activity and stability, and focused on as promising air cathode materials for metal-air battery. In this work, we report a novel method to fabricate cobalt (Co) single-atom species supported on porous carbon substrate using poly-(1,4-diethynylbenzene) (PDEB) chain as a new carbon substrate. Nitrogen doped PDEB chain combined with cobalt single-atom (Co-N-PDEB) shows excellent ORR and OER bifunctional catalytic performance with 1.08 V of oxygen electrode activity due to the synergistic effect between unique meso and macroporous carbon matrix with doped Co-N4 moiety. Finally, Co-N-PDEB air cathode adopted hybrid sodium (Na) air battery exhibits outstanding charge-discharge characteristics with low overpotential gap (0.296 V) and high round trip efficiency (91.02 %).

Soot as electrode coating for supercapacitor prototypes

Black powders were prepared from chimney soot by means of treatment with different solvents and drying. The powders were used to prepare inks, which were deposited on copper foils. The as prepared electrodes were assembled as supercapacitor structures with KOH as electrolyte. The charge-discharge characteristics were measured to evaluate the electrical capacitance and to compare the technology for soot treatment. The soot was studied as a source before and after treatment using IR spectroscopy, XRD and SEM EDX.

Supercapacitors as elements increasing the efficiency of photovoltaic installation

The main purpose of the research is to check an influence of supercapacitors as the elements increasing the efficiency of short-period energy storage in photovoltaic installations. Their task will be to substitute the batteries or enhance their performance as the energy bank. For the model storage setup consisting of six supercapacitors, the work charge-discharge characteristics were determined. Additionally, an influence of storage time on the amount of charge accumulated inside the battery was tested. Then the examined setup was coupled with a conventional PV module by the charge regulator system and tested in laboratory and under real operating conditions. Obtained results proved that the use of supercapacitors as buffer elements in energy storage system of photovoltaic installation can significantly increase operation lifetime and reliability.

Studying the effects of bismuth on the electrochemical properties of lead dioxide layers by using the in situ EQCM technique

The charge-discharge characteristics and the aging mechanism of PbO2 layers doped with bismuth in contact with sulfuric acid solutions were studied by using combined cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM) techniques. For this purpose, thick lead dioxide layers (non-doped and doped with Bi) were electrodeposited on gold substrate from aqueous solutions of Pb(NO3)2 dissolved in nitric acid and they were investigated in sulfuric acid media. Based on the electrochemical and the mass change responses, it is concluded that during the electrodeposition, bismuth influences the structure of the PbO2 formed. Bi(III) also inhibits the oxidation of lead sulfate and affects the reduction kinetics of lead dioxide. During successive cyclization (aging), the presence of bismuth accelerates the hydration of PbO2.

A Solid-State Lithium-Ion Battery: Structure, Technology, and Characteristics

A design of a fully solid-state thin-film lithium-ion battery prototype and results of its being tested are presented. It is shown that the specific features of its charge–discharge characteristics are associated with the change of the Fermi level in the electrodes and are due to changes in the concentration of lithium ions in the course of charge–discharge. The specific capacity characteristics of the prototype were determined and found to be comparable with the characteristics of commercial lithium-ion batteries.

МАТЕМАТИЧЕСКАЯ МОДЕЛЬ ФУНКЦИОНИРОВАНИЯ ГИБРИДНОЙ СИСТЕМЫ ЭНЕРГООБЕСПЕЧЕНИЯ В СОСТАВЕ СТЕНДА ОТЛАДКИ И СОПРОВОЖДЕНИЯ АНПА

The aim of the research is to develop a complex of mathematical models that provide initial data for a mathematical model of the hybrid energy supply system for subsequent integration into the stand for debugging and maintenance. The work is a development of the previously published mathematical model of the functioning of the hybrid energy supply system of an autonomous un-derwater vehicle. In the work, based on the results of the analysis of the goals and objectives of modeling, mathematical models of electric power sources — a storage battery and an electro-chemical generator — are developed. Since control over the operating parameters of the battery and the electrochemical generator depends on the parameters of the vehicle’s movement, addi-tional mathematical models of the marching propulsion engine and the integrated control system of the vehicle have been developed. The external conditions for the functioning of the vehicle and the route task were set in a specially developed tactical situation simulator. Based on the theory of integrated hierarchical modeling with variable resolution, the most appropriate degree of detail of the developed mathematical models was determined. In view of the need to take into account the non-uniformity of gas blowing of fuel elements in an electrochemical generator, the mathematical model is based on solving a non-linear system of equations, including the Navier-Stokes equation, equations of conservation of momentum, energy and charge. When developing a mathematical model of the battery, the uneven charge of individual batteries was taken into account; The math-ematical model took into account the parameters of individual batteries according to their manu-facturer. The simulation results were the charge-discharge characteristics of the battery. In the mathematical model of the main consumer of electricity - the marching propulsion - the depend-ence of the generated thrust on the required speed of the vehicle is implemented, which allowed to obtain the amount of electricity consumed by the marching propulsion. In the mathematical model of an integrated control system, depending on the current position of the vehicle, motion control-lers are implemented to form control elements of the propulsion system, providing typical modes of maneuvering the vehicle. In addition, the control of the functioning parameters of the hybrid ener-gy supply system was implemented - switching of electric power sources, switching of battery charge processes. In the mathematical model of a tactical situation simulator, the possibilities of defining a route and external conditions are realized. In addition, a model of the vehicle movement was implemented taking into account the forces and moments acting on the vehicle. The developed complex of mathematical models, which provides the data with a mathematical model of the func-tioning of the hybrid energy supply system, can be used as a part of the stand for debugging and maintenance of an autonomous underwater vehicle.

Deposition and performance of all solid-state thin-film lithium-ion batteries composed of amorphous Si/LiPON/VO-LiPO multilayers

Recently, thin-film lithium-ion batteries have attracted considerable attention as the micro-power sources for micro-sensors. In this study, we fabricated all solid-state thin-film lithium-ion batteries composed of amorphous multilayers and evaluated their charge-discharge characteristics in atmospheric conditions. The thin-film batteries were composed of an amorphous multilayer structure of lithium-doped vanadium oxide, lithium phosphorus oxynitride (LiPON), and Si as cathode, electrolyte, and anode, respectively. To obtain a good interface with the LiPON electrolyte, we deposited a multilayer cell structure by successive deposition in a vacuum chamber with a multi-target sputtering machine equipped with a movable shadow mask. We measured the charge and discharge characteristics of the thin-film batteries under atmospheric conditions without protection layers on the thin-film batteries. We observed large unit area capacities of 32.8 and 15.7 μAh/cm2 at the first charge and discharge cycle, respectively, in the voltage range of 0.5–3.0 V.

Твердотельный литий-ионный аккумулятор: структура, технология и характеристики

The design description and test results of an all solid-state thin-film lithium-ion battery are provided. It is shown that the features of its charge-discharge characteristics are associated with a change in the Fermi level of the electrodes and are caused by a change in the concentration of lithium ions in the course of the charge-discharge. The specific capacitive characteristics of the layout are determined, which are comparable with the characteristics of industrial solid-state lithium-ion batteries.

Research of iron (III) molybdate and iron (II) molybdate as catode materials for lithium power sources

The synthesis of finely divided iron (III) and (II) molybdates from aqueous solutions was carried out. Electroactive materials based on synthesized compounds and thermally expanded graphite have been prepared. Lithium current sources with cathodes were constructed based on these materials and their charge-discharge characteristics were determined. The open circuit voltage of element 1 is close to 3 V. During discharge, the voltage sharply decreases to 2 V for the first discharge-charge cycle (2.35 V for the second discharge-charge cycle) and decreases from 2 to 1 V. during discharge. further discharge results in a faster decrease of the discharge current and voltage. The results obtained indicate that the discharge characteristics of the element after manufacture are relatively good. The following discharge-charge cycles show a deterioration of the discharge characteristics by reducing the energy and current efficiency. Judging by the amount of energy received in 0 discharge cycles and the energy expended on the charge of the element, it can be stated that part of the lithium ions is intercalated into the cathode material irreversibly. After completion of the 0 discharge cycle, the composition of the generated recovery product based on the amount of electricity obtained can be represented by the formula Li 2,48 Fe 2 (MoO 4 ) 3 . In the 1st and 2nd cycles, the number of lithium ions intercalated into the cathode material is x = 1.68 and x = 0.88, respectively. On the discharge curve of element 2, you can select the area where the voltage varies relatively slowly from 3.5 V to 2.5 V, which corresponds to the number of intercalated lithium ions x = 0,15, as well as the second area for which a fairly stable value of voltage 1 is observed. 5V and a slight downward drift. A fairly stable element discharge occurs up to a lithium content of x ≤ 0.56. After completion of the 0 discharge cycle, the composition of the generated recovery product based on the amount of electricity obtained can be represented by the formula Li 0,71 FeMoO 4 . After the recharge, the corresponding plateaus became much narrower and the voltage value decreased significantly. The results obtained indicate that the discharge characteristics of the element after manufacture are relatively good, and for subsequent cycles of discharge-charge about the poor turnover of the processes, which is indicated by the small values of the coefficients of return. In the 1st and 2nd cycles, the number of lithium ions intercalated into the cathode material is x = 0.32 and x = 0.11, respectively. These data indicate that a large number of lithium ions are irreversibly incorporated into the structure of molybdate iron (II) and as the discharge-charge cycles increase, this amount increases. Keywords: iron molibdate, lithium power sources, charge-discharge properties.

Simulation Modeling and Charge–Discharge Characteristics of a Zinc–Nickel Single-Flow Battery Stack

Simulation Modeling and Charge–Discharge Characteristics of a Zinc–Nickel Single-Flow Battery Stack

A novel cathodic composite in lithium ion battery based on LiNi<SUB align="right">0.7Co<SUB align="right">0.3O<SUB align="right">2, Li<SUB align="right">2MnO<SUB align="right">3, and LiCoO<SUB align="right">2 combination: synthesis and characterisation

Various composites including (1-x-y) LiNi0.7Co0.3O2, xLi2MnO3 and yLiCoO2 systems were synthesised using the sol-gel method. Stoichiometric weights of the LiNO3, Mn(Ac)2·4H2O, Co(Ac)2·4H2O, Ni(NO3)2·6H2O for preparing of 28 samples have been used. We found that the sample Li1.167Ni0.117Co0.699Al0.017Mn0.167O2 with Al doped is the best composition for cathode material in LIBTs. Obviously, the weight of cobalt used in this sample is lower compared to LiCoO2 which is an advantage in view point of cost and toxicity. Charge-discharge characteristics of the mentioned cathode materials were investigated by performing cycle tests in the range of 2.4-4.6 V. Our results confirmed that this kind of system can help removing the mentioned disadvantage of cobalt with high efficiency.

Моделирование заряд-разрядных характеристик суперконденсаторов на основе эквивалентной схемы с фиксированными параметрами

The paper shows the possibility of describing the charge-discharge characteristics of supercapacitors with porous carbon electrodes using a simple equivalent circuit with constant capacitances and resistances. Using numerical simulation, it is shown that there is a relationship between the parameters of the equivalent circuit and the pore structure of the electrode material. The simulation results also indicate the inhomogeneous nature of the charging of various groups of pores of the electrode material in the structure of the supercapacitor.

The effect of the geikeilite (MgTiO3) nanofiller concentration in PVdF-HFP/PVAc–based polymer blend electrolytes for magnesium ion battery

Magnesium ion–conducting polymer electrolyte is one of the necessary components of current rechargeable magnesium batteries because of its good interfacial contact with electrodes and efficient mechanical properties. In the recent analysis, we described synthesis and characterization of a composite polymer electrolyte (CPE) based on poly (vinylidene fluoride-co-hexafluoro propylene)/poly vinyl acetate, salt as magnesium perchlorate, and various weight percentages (wt %) of geikeilite filler (MgTiO3) by the solution casting method with tetrahydrofuran as a solvent. Structural analysis, Thermogravimetric analysis (TGA), complex impedance spectroscopy, ionic transference number analysis, linear sweep voltammetry (LSV) and cyclic voltammetry (CV) studies exhibit promising characteristics of prepared CPEs for appropriate utilization in magnesium battery application. The CPEs display high thermal constancy, high ionic conductivity (~ 5.80 × 10−3 Scm−1 at 30 °C), high magnesium transference number (= 0.34) and high electrochemical stability window. Dielectric properties of polymer films are analyzed and discussed. The electrochemical stability of 1.4 V and 2.4 V was get for 6 wt% incorporated MgTiO3 nanofiller system R3 polymer electrolytes, respectively, utilizing linear sweep voltammetry, cyclic voltammetry, and charge-discharge characteristics. The prepared CPE is expected to be a promising electrolyte candidate for magnesium battery utilization.

Аналіз технічних характеристик акумуляторних батарей і систем заряджання електромобілів

Electric cars are a promising area for the development of infrastructure and transport. Almost all international automotive corporations are investing heavily in the development of electric vehicles. The article presents the classification of electric vehicles and reviews the technical characteristics of batteries and their charging systems. To date, the most promising are lithium-ion batteries. They have the following advantages: high efficiency in the process of charge-discharge, high density of electric energy (kW·h/kg). At the same time, the relative disadvantage of lithium-ion batteries is the small number of charge-discharge cycles (about 500 cycles), which corresponds to about 250 thousand km for the Tesla Model S electric car, after which the battery must be replaced. The basic energy parameters and charge-discharge characteristics of lithium-ion batteries used in Tesla electric vehicles are presented. Four types of charging stations are identified and classified. According to what the first type – describes the process of charging an electric vehicle directly from a single-phase network. The second type has a difference from the first by the presence of electrical protection. The third type is the charge of an electric vehicle with a three-phase AC voltage. The fourth type is a charge with direct current and high power, which makes it possible to carry out the charge process faster. The types of internationally standardized plugs for charging electric vehicles are considered: CHAdeMO – a standard developed inJapanandChina, CSS1 – North American, CSS2 – European and TeslaSupercharger standard. One of the most important indicators of electric vehicles is the charge-discharge characteristics of batteries and their chargers. This is due to the maximum range for one battery charge and efficiency, that is, the actual financial cost of electricity. In existing chargers with significant values of the charge current (type 4 charging), large losses of electricity occur, therefore, the issue of developing our own technical solutions to improve the technical characteristics of charging stations of electric vehicles is relevant.

Investigation of the electrochemical behaviour of lead dioxide in aqueous sulfuric acid solutions by using the in situ EQCM technique

The charge-discharge characteristics and the aging mechanism of PbO2 layers in contact with sulfuric acid solutions of different concentrations (1.5–5.0 M) were studied by using combined cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM) techniques. For this purpose, thick lead dioxide layers were electrodeposited on gold substrate from aqueous solutions of Pb(NO3)2 dissolved in nitric acid. Based on the electrochemical and the mass change responses, it was found that in more concentrated solutions of H2SO4, the main reduction reaction was the transformation of lead dioxide to lead sulfate. However, in less concentrated sulfuric acid media, the transformation of lead dioxide to lead(II) ion became the main reaction. These Pb2+ ions transformed into lead sulfate crystals later by a chemical reaction. Because the electrochemical oxidation of lead sulfate is less favourable in sulfuric acid medium of higher concentrations, thus, PbO2 layers cannot be tested by continuous cyclization, which is necessary to study their aging parameters. Therefore, a delay step before each cyclic voltammogram was applied while the non-conductive lead sulfate dissolves or alternatively, by applying a pre-oxidation step prior to each cyclic voltammetry experiment to produce electrochemically significant amount of lead dioxide which can be reduced during the following negative potential sweep.

Selection of Optimum Binder for Silicon Powder Anode in Lithium-Ion Batteries Based on the Impact of Its Molecular Structure on Charge–Discharge Behavior

The high-capacity and optimal cycle characteristics of the silicon powder anode render it essential in lithium-ion batteries. The authors attempted to obtain a composite material by coating individual silicon particles of µm-order diameter with conductive carbon additive and resin to serve as a binder of an anode in a lithium-ion battery and thus improve its charge–discharge characteristics. Structural strain and hardness due to stress on the binder resin were alleviated by the adhesion between silicon or copper foil as a collector and the binder resin, preventing the systematic deterioration of the anode composite matrix immersed in electrolyte compositions including Li salt and fluoride. Moreover, the binder resin itself was confirmed to play a role of active material with occlusion and release of Li-ion. Furthermore, charge–discharge characteristics of the silicon powder anode active material strongly depend on the type of binder resin used; therefore, the binder resin used as composite material in rechargeable batteries should be carefully selected. Some resins for binding silicon particles were investigated for their mechanical and electrochemical properties, and a carbonized polyimide obtained a good charge–discharge cyclic property in a lithium-ion battery.

High‐performance tin‐oxide supercapacitors using hydrazine functionalising assisted by hydrogen plasma treatment

For the first time, the effects of adding hydrazine solution to tin-oxide sol–gel to be used as an electrode in high-performance supercapacitors have been studied. The mixed solution has been spin-coated on stainless steel foils as substrates followed by exposing to hydrogen plasma treatment. The results show the effectiveness of adding hydrazine to tin-oxide sol–gel, compared to pure tin-oxide sol–gel. The electrochemical tests such as cyclic-voltammetry and charge–discharge characteristics have been conducted, and the findings demonstrate the favourable contribution of adding hydrazine in increasing the capacitance of the supercapacitor. The physical properties of the tin-oxide material have been analysed by means of FESEM, XRD, TEM, FT-IR spectroscopy and Raman spectroscopy to have a better understanding of preparation procedure and better insight in material synthesis. The electrochemical tests demonstrate a high capacitance of 18 mF/cm2 for the sample treated with hydrazine during the sol–gel processing which is around 40% higher than the merely prepared tin-oxide sample. The measured values for the capacitance versus rate show a rather linear correlation between these parameters, further corroborating an electric-double layer-based performance for such devices.

Effect of Al2O3 on structural and dielectric properties of PVP-CH3COONa based solid polymer electrolyte films for energy storage devices

Nanocomposite polymer (NCP) films were prepared by doping sodium acetate (CH3COONa) in polymer of polyvinyl pyrrolidone (PVP) by complete dispersion of aluminum oxide (Al2O3) with different wt% proportions using solution cast method. The acquired NCP films were systematically characterized. The crystalline structure of the prepared NCP films was confirmed by XRD. The little agglomeration and grain sizes involved in the films were analyzed by SEM. The chemical bond formation and interchange reaction between the host, dopant salt and the nanofiller were confirmed by FTIR and Raman. The lowest energy bandgap values were observed to be 3.0 eV for the synthesized film with wt% ratio of PVP + CH3COONa:Al2O3 (80:20:1%). The highest ionic conductivity was found to be 1.05 × 10−3 S/cm for the prepared film with wt% ratio of PVP + CH3COONa:Al2O3 (80:20:1%). From the charge discharge characteristics it was concluded that the film with wt% ratio of PVP + CH3COONa:Al2O3 (80:20:1%) possesses long durability when compared to the other prepared films.

Improved electrochemical behavior of metal oxides-based nanocomposites for supercapacitor

This paper investigates the synthesis and enhanced electrochemical behaviors of ZnO and NiO/ZnO nanocomposites for electrode material of supercapacitors. ZnO and NiO/ZnO nanocomposites were produced via sol–gel technique. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) were used to determine the size and structure of as-synthesized nanomaterials, respectively. The capacitive behavior and charge–discharge characteristics of the electrode using ZnO and NiO/ZnO nanocomposites (as active material) were individually probed with the help of cyclic voltammetry (CV) and galvanostatic charge-discharge tests, respectively. The specific capacitance of nanocomposites-based electrode calculated from galvanostatic charge-discharge tests was 469[Formula: see text]F [Formula: see text] at the scan rate of 1[Formula: see text]mA [Formula: see text] in 1M Na2SO4 electrolyte. The power density and energy density at the current density of 1[Formula: see text]mA [Formula: see text] were determined as 1458.33[Formula: see text]W [Formula: see text] and 91.14[Formula: see text]Wh[Formula: see text][Formula: see text], respectively. Hence, NiO/ZnO nanocomposites could be reckoned to be a promising electrode material for supercapacitor while comparing to ZnO-based electrode material.

Ex situ investigation of exothermal behavior and structural changes of the Li3PS4- LiNi1/3Mn1/3Co1/3O2 electrode composites

Sulfide-based all-solid-state lithium batteries are expected to be a next-generation power source because of their high energy density, good charge–discharge characteristics, and incombustibility. A positive electrode composite comprising LiNi1/3Mn1/3Co1/3O2 (NMC) and Li3PS4 (LPS) glass electrolyte shows excellent charge–discharge cycle characteristics. To understand exothermal reactions during the heating process of this battery material, structural and morphological changes were investigated mainly by ex situ X-ray diffraction measurements as well as ex situ transmission and scanning electron microscopy observations. We found that a number of transition-metal sulfides, such as MnS and CoNi2S4, and Li3PO4 nanocrystallites were formed in a sample heated at a temperature above the exothermic peak temperature. In addition, no substantial difference was observed in the behavior of these structural and morphological changes due to charge and discharge cycles. The formation of transition-metal sulfides and Li3PO4 crystalline phases suggests that, when exposed to real cell operating environments, LPS and NMC undergo a chemical reaction via heat treatment, which directly leads to the exothermal reactions.