Influence of Deep-discharge Rate on Recycle Process of High Energy Density Traction Batteries

Lithium-ion traction batteries are increasingly use in transportation such as electric vehicles and buses. In order to reduce the life cycle cost of traction battery, material recycling is a technical route that must be considered. Deep-discharge is one of the necessary steps in the process of battery disassembly and material recycle, but the thermal stability and internal material changes caused by deep discharge will affect the subsequent recycle processes. In this paper, we study the influence of deep-discharge rate on recycle process of a commercial traction battery with LiNi1/3Co1/3Mn1/3O2 cathode and graphite anode. Combine with multi-analysis methods, the evolution of an electrode structure under different deep-discharge current densities is systematically studied. The results show that the deep-discharge current density will have different effects on the internal structure of the battery and will affect its thermal safety.

Electrochemical Hydrogenation and Corrosion Behaviour of LaNi5-xGex (x = 0.3 and 0.6) Alloys

The capacitive and kinetic parameters of hydride electrodes obtained on the basis of single-phase LaNi5-xGex alloys (x = 0.3 and 0.6) were related to their corrosive properties. The content of the article is important from the point of view of the improvement of LaNi5 type materials for hydrogen energy storage used as anodes in NiMH batteries. The presence of large amounts of germanium (10% at.) in the alloy results in much less surface degradation compared to the low-germanium alloy (5% at.), which, on the one hand, leads to an improvement in the resistance of the high-germanium LaNi4.4Ge0.6 alloy to long-term cycling, but on the other hand, contributes to lower hydrogen absorption by this material. The maximum discharge capacity of 293 mAh g−1 was obtained for the low-germanium alloy using a charge/discharge current density of 185 mA g−1. The studied electrode also shows a lower tendency to self-discharge and a clearly higher exchange current density.

Application of Glow Discharge Plasma for Cleaning (Activation) and Modification of Metal Surfaces while Welding, Brazing, and Coating Deposition

As known, the surface phenomena play a crucial role in the formation of strong interatomic bonds while joining dissimilar materials and the deposition of metal films. Thus, the presence of various contaminants, including oxides, on the metal surface reduces drastically the metal surface energy, thereby, preventing the diffusion processes in the contact zone and wetting them with liquid solder and adhesion of condensed films on the substrate surface. As a result, the processes of cleaning (activating) of metal surfaces before welding or coatings’ deposition begin to play a significant role. In some cases, metal surfaces have to be modified in order to give them the desired properties. Recently, for activation and modification of surfaces before welding and coatings’ deposition, gas-discharge plasma of abnormal glow discharge is widely used. The latter allows treating the surfaces of different configurations, including internal cavities, and various areas from units to tens of thousands of square centimetres. This review contains the results of research on the activation and modification of metal surfaces with low-energy ions (< 10 keV) initiated in the plasma of an abnormal glow discharge for welding, brazing, and coatings’ deposition. Particularly, we present results of studies of ion treatment with the glow discharge surface of samples, which are made of steels С45 and DC04, a number of active metals and alloys as well as chromium-containing steels 41Cr4, X20Cr13, and X6CrNiTi18-10, which possess the chemically and thermally stable Cr2O3 oxides on their surfaces. The decisive influence on the efficiency of purification and modification of metal surfaces with glow discharge by means of such regime parameters as electrode voltage, discharge current density, working chamber pressure, and ion exposure time is indicated. The optimal values of these parameters, in most cases, are determined by the technological conditions of the process and vary in the following ranges: U = 1500–3500 V, J = 0.4–1 mA/cm2, P = 3.99–7.98 Pa, t = 120–300 s, respectively.

Facile Hydrothermal Synthesis of Fe2O3/rGO Composites for Low-Cost Supercapacitors

In this work, Fe2O3/rGO composites with high capacitive performance were synthesized via a facile hydrothermal route. The morphological and structural characteristics of the synthesized material were obtained by using X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The three-electrode system was employed for investigating the electrochemical performance in 6 M aqueous electrolytic solution of KOH. The electrochemical data reveals that the Fe2O3/20%rGO shows as high as 171 F g[Formula: see text] specific capacitance at 1 A g[Formula: see text] discharge current density within the operated voltage window −0.9[Formula: see text]V–0[Formula: see text]V, which is 55% higher than that of the bare Fe2O3. After 1000 cycles, the capacity reservation was retained at 74%. The results indicate that the synthesized Fe2O3/rGO material could be a potential candidate for applications in an environmentally friendly commercial electrode.

Discharge of hydronium ions on metal cathodes in the presence of pyridine

In this work, studies have been carried out on the electrochemical reduction of hydrogen (hydronium ion) from acidic aqueous solutions in the presence of an organic substance – pyridine. Electrolysis was carried out in an electrolyte with a sulfuric acid content (0.18; 0.36 M) with a pyridine additions of 8.4·10-3 M. Potentiostatic studies were carried out on a Potentiostat P-30Jcom Elins potentiostat using a three-electrode cell. Working electrodes (cathodes) were made of M1 copper with an area (S) of 0.09 cm2; aluminum (AD1) S – 0.125 cm2, zinc (Ts0A) S – 0.35 cm2, lead (Cl) S – 0.20 cm2, auxiliary (anode) – from a platinum plate with an area of 0.20 cm2, reference electrode – silver chloride (AgCl/Ag). In potentiometric measurements, the results are presented according to the average data obtained for 30 s of electrolysis in the potential range (-950 ÷ -1100 mV for AgCl/Ag), and in studies in the galvanostatic mode at current densities from 0 to 110 mV/cm2, the results are presented as average data, obtained in the initial 5 s of the process. The paper presents comparative data on the electrokinetic parameters studied under the same conditions of hydrogen discharge reactions at different cathodes in electrolytes with a sulfuric acid content of 0.36 M. It is shown that the highest discharge current density of the hydronium ion (Н3О+) is achieved at the copper electrode, and the lowest at the lead electrode. With the addition of 8.4∙10-3 M pyridine to the electrolyte, the reduction of hydrogen cations is somewhat reduced on the electrodes used, except for lead. The transfer coefficients of the hydrogen discharge at all electrodes are low, and with the addition of pyridine they decrease even more. The low transfer coefficients indicate that the process of the hydronium ion discharge proceeds in a non-activation mode. The lowest exchange current is recorded at the copper and lead electrode. At the zinc electrode, the exchange of current is one to two orders of magnitude higher than at the other electrodes, so it can be noted that at this electrode the system under consideration is closer to the equilibrium of state. The order of the reaction of the course of electrolysis by the hydronium cation on the copper, aluminum and zinc electrodes is close to unity. The addition of pyridine leads to a slight decrease in the order of the reaction. This is due to the fact that pyridine molecules in acidic solutions exist in the form of pyridinium ion, which is reduced at the cathode. In this case, a significant amount of hydrogen is absorbed, which should explain the decrease in the order of the reaction with respect to the hydronium ion in the presence of pyridine additives. The obtained low values of the transfer coefficients indicate that, during the discharge of hydronium ions, the process is limited to a greater extent by the concentration polarization. The diffusion nature of the reduction of hydronium ions in electrolytes with a sulfuric acid concentration of 0.18 and 0.36 M is also evidenced by data taken in a dynamic mode.

Use of Carbon Additives towards Rechargeable Zinc Slurry Air Flow Batteries

The performance of redox flow batteries is notably influenced by the electrolyte, especially in slurry-based flow batteries, as it serves as both an ionic conductive electrolyte and a flowing electrode. In this study, carbon additives were introduced to achieve a rechargeable zinc slurry flow battery by minimizing the zinc plating on the bipolar plate that occurs during charging. When no carbon additive was present in the zinc slurry, the discharge current density was 24 mA∙cm−2 at 0.6 V, while the use of carbon additives increased it to up to 38 mA∙cm−2. The maximum power density was also increased from 16 mW∙cm−2 to 23 mW∙cm−2. Moreover, the amount of zinc plated on the bipolar plate during charging decreased with increasing carbon content in the slurry. Rheological investigation revealed that the elastic modulus and yield stress are directly proportional to the carbon content in the slurry, which is beneficial for redox flow battery applications, but comes at the expense of an increase in viscosity (two-fold increase at 100 s−1). These results show how the use of conductive additives can enhance the energy density of slurry-based flow batteries.

Optimizing Discharge Capacity of Graphite Nanosheet Electrodes for Lithium–Oxygen Batteries

Lithium–oxygen (Li-O2) batteries require scalable air electrode concepts and a sensible choice of operation parameters to achieve their promised energy densities. Furthermore, different test parameters are often investigated individually, but rarely brought together in order to optimize the discharge process and unlock the full discharge capability of an air electrode. In this work, we present a highly porous electrode based on graphite nanosheets (GNS) and discuss the impact of the discharge current density and the oxygen pressure as battery test parameters, as well as the electrolyte salt and volume, on the discharge behavior. In particular, changing the electrolyte salt from LiNO3 to LiTFSI proved to be an important step towards better cell performance, because synergistic effects of the electrolyte and GNS greatly enhance the carbon-specific capacity. The optimized combination of the aforementioned parameters enabled a remarkably high discharge capacity of 56.3 mAh/cm2 (5860 mAh/gcarbon) obtained at 150 µA/cm2 (15.6 mA/gcarbon), resulting in the almost complete conversion of the lithium anode. These experimental results are an important step towards practical high-capacity air electrodes for Li-O2 batteries.

Numerical Modeling and Analysis of the Performance of an Aluminum-Air Battery with Alkaline Electrolyte

A numerical model is created to simulate the discharge performance of aluminum-air batteries (AABs) with alkaline electrolyte. The discharge voltage and power density, as a function of the discharge current density, are predicted for the modeled AAB and compared with experimental measurements. A good agreement between model and experiment is found. The effect of various model parameters on the battery performance is studied by adjusting the parameters within a suitable range. The results show that electrolyte thickness is a key factor that can strongly increase the power density and the corresponding current density as the electrolyte thickness decreases. The peak of power density is increased by a factor of two if the electrolyte thickness is reduced from 7 mm to 3 mm. The alkaline concentration is also an important factor, since both the voltage and power density curves are significantly raised as the NaOH concentration is increased from 1 to 4 mol/L. The partial oxygen pressure plays a secondary role in performance improvement. The peak of power density is increased by 35% using pure oxygen in the air electrode. In addition, the active specific surface area of the catalyst layer also affects the discharge capability of the AAB system.

One-Pot Synthesis and Characterization of VO2(B) with a Large Voltage Window Electrochemical Performance in Aqueous Solution

B-type vanadium dioxide (defined as VO2(B)) nanobelts were synthesized through using commercial ammonium metavanadate, oxalic acid via one-step hydrothermal technique. The structure of VO2(B) was characterized using different instruments. N2 adsorption-desorption isotherms revealed that the VO2(B) nanobelts were porous structures where BET surface area was 10.4 m2·g−1, the pore volume was 0.0687 cm3/g, and the average pore size was 42.7 nm. Furthermore, the VO2(B) nanobelts as supercapacitors electrode exhibited a large voltage window (−0.8~1.0 V). The measured capacitance was based on the pseudocapacitance. When the discharge current density is 0.5, 1, and 10 A·g−1, the VO2(B) shows the specific capacitance of 287, 246, and 222 F·g−1, respectively.