Electrodeposited Dendrite-Free, Nano-Columnar 3D Lithium Anodes and Their Application in Lithium Sulfur Batteries with 3D Sulfur Cathodes

  • Fig. 1: Schematic view of a Li/S battery with 3D battery electrodes and Celgard 2500 separator
    Fig. 1: Schematic view of a Li/S battery with 3D battery electrodes and Celgard 2500 separator

In this work, homogeneous, dendritefree, nano-columnar lithium electrodeposition on 3D nickel foam from a 1 M lithium hexafluorophosphate (LiPF6) propylene carbonate (PC) electrolyte under convection has been performed successfully. The surface morphology and the thickness of the deposition can be varied depending on the electrodeposition parameters. In this way, it is possible to improve the surface area and reduce the amount of lithium in the cell, e.g. to only 50 % lithium excess, increasing cell safety. The new lithium plated 3D anode was developed to be combined with a 3D composite electroplated sulfur cathode, ensuring low local current densities at both, cathode and anode, which lowers overpotentials and therefore increase the cell efficiency. Furthermore, the porous electrodes can accommodate a larger amount of electrolyte, which is beneficial for an increased cycling stability. The results show that despite the reduction of lithium weight by a factor of 12 compared to a battery with a commercial 1.5 mm thick 2D lithium foil anode, the overall battery capacity on cell level, using cathodes with equal sulfur content, could even be improved.


    

The Use of Immersed Electrochemical Modules in Plating Shops for the Regeneration of Process Solutions and Purification of Water in Reclaim Tanks

  • Tab. 1: Applications of electrochemical processes for the regeneration of chromate-based solutions
    Tab. 1: Applications of electrochemical processes for the regeneration of chromate-based solutions

Immersed electrochemical module (IEM) is an electrochemical half-cell with one or two ion-exchange membranes and an inner electrode. IEM is immersed directly into a tank with a process solution in order to produce certain changes in its composition, for example, to recover nickel ions from spent electroless nickel plating solutions. Another area of application is to maintain the stable composition of process solutions such as various etchants used in the manufacture of PCBs, stripping and passivating solutions based on chromic acid and its salts. Stabilizing is achieved by anodic regeneration of an oxidant (chromate, ferric, cupric or persulfate ions) which are consumed in the course of the operation of the solution, by removing accumulating reaction products (various metal ions) and maintaining desirable pH value in the process solution. Continuous operation of such modules allows to eliminate periodic dumping and to reduce considerably consumption of chemicals used for replenishments. IEMs are used in many plating shops for continuous regeneration of chromate-based zinc passivating solutions. Another area of application of IMF is a continuous purification of water in reclaim tanks which allows to reduce the consumption of fresh water for rinsing and the amount of waste water. Metals such as zinc, copper, cadmium and tin are recovered from reclaim tanks equipped with IEMs and are usually returned into plating tanks. Nickel metal is utilized in some other way. Chromic acid which is recovered from reclaim tanks with IEMs contains no cationic impurities. It is returned into chromium plating or passivating process solutions. The operation of IEMs in reclaim tanks after chromium plating, anodizing or passivating in chromate-containing solutions allows to reduce the consumption of chemicals and the amount of waste. Installation of IEM does not need any additional floor space, pipe lines, etc. They are especially effective in chromating tanks and small-scale cadmium plating lines, where their use can solve problems related with the environment protection. IEMs are used in Russia in many captive plating shops.


    

Characterization and influence on the fatigue properties of the metal-turn-over of an electroless nickel coating on an AlCuMgFeNi alloy

  • Fig. 3: Etched cross section of the coatings in the as deposited condition of (a) MTO 0, (b) MTO 2, (c) MTO 3.5; the substrate material is in the lower part of the picture. The coatings show the lamellar structure as well as some defects reaching from the substrate to the surface
    Fig. 3: Etched cross section of the coatings in the as deposited condition of (a) MTO 0, (b) MTO 2, (c) MTO 3.5; the substrate material is in the lower part of the picture. The coatings show the lamellar structure as well as some defects reaching from the substrate to the surface

In this paper the influence of a mid-phosphorous electroless nickel coating on EN-AW 2618A was studied. Special emphasis was put on the metalturn-over (MTO) and a heat treatment on the coating properties and their influence on the fatigue properties. The increasing MTO leads to an increase in phosphorous content resulting in a reduction of hardness, while the ductility is much less affected. The low temperature heat treatment increases the hardness through a crystal growth. The fatigue tests show, that the electroless nickel coating can both have a positive as well as a negative influence on the fatigue properties. At higher mechanical stresses the deposit tends to reduce the lifetime, while at lower loads the lifetime gets increased. The reduction of lifetime is caused by defects in the coating which act as stress concentrators. An increase in MTO leads to a higher amount of coating defects and therefore a higher possibility for a reduction of the lifetime. Further research has to focus on the growth mechanisms of those defects since their influence seems to be more significant than other factors like the phosphorous content.


    

Corrosion Inhibition of Carbon Steel in hydrochloric acid medium using Gliclazide drug

  • Fig. 10: The Nyquist (a) and Bode (b) curves for oxidation of CS in 1 M HCl in the nonexistence and existence of various doses of Gliclazide at 25 °C
    Fig. 10: The Nyquist (a) and Bode (b) curves for oxidation of CS in 1 M HCl in the nonexistence and existence of various doses of Gliclazide at 25 °C
The role of Gliclazide as corrosion drugs for CS in 1 M HCl have been studied by using weight loss (WL), Hydrogen evaluation (HE), potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS) and Electrochemical frequency modulation (EFM) techniques. Weight loss (WL) studied at various temperatures between (25 – 45oC) but Hydrogen evaluation (HE), Open circuit potential (EOCP) and all electrochemical studied at 25oC and seen that the gliclazide studied are mixed type drug. The effect of temperature on corrosion inhibition, the activation and the thermodynamic of adsorption parameters were determinate. Electrochemical impedance was utilizing to examine the inhibition of corrosion and the mechanism. The existence of the Gliclazide in the solution rise the charge transfer resistance and reducing the capacitance of the double layer. The adsorption of the Gliclazide on the surface of CS was found to obey with Langmuir adsorption isotherm and discussed the thermodynamic parameters (ΔGo, ΔHo and ΔSo) that were determinate. The morphology of inhibition of Gliclazide on CS surface was analyzed by scanning electron microscope (SEM) technology, energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM), all examine techniques illustrate the formation of thin film from Gliclazide inhibitor adsorbed on the metal surface.It was found the adsorption process is spontaneous and increases, with increasing of inhibition efficiency.


    

Delonix Regia Leaf Extract as Environmental Friendly and Safe Corrosion Inhibitor for Carbon Steel in Aqueous Solutions


Delonix regia leaf extract activity as a green corrosion inhibitor (environmental friendly) for carbon steel (CS) in 1M HCl has been studied using weight loss (WL), potentiodynamic polarization (PP), electrochemical frequency modulation (EFM) and electrochemical impedance spectroscopy (EIS). The weight loss results show that Delonix regia leaf extract is an excellent corrosion inhibitor. The inhibition efficiency (IE) increases with temperature from 25 to 45oC, reaching a maximum value of 78.8 % at the highest concentration of 300 ppm at the temperature of 45oC. Polarization measurements demonstrate that the Delonix regia leaf extract acts as a mixed type inhibitor. Nyquist plot illustrates that on increasing Delonix regia leaf extract dose, the charge transfer increases and the double layer capacitance decreases. The adsorption of Delonix regia leaf extract on CS obeys Temkin adsorption isotherm.