Improved cycle life performance of Zn/NiOOH cells using a stabilized zinc electrode (original) (raw)
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Journal of Solid State Electrochemistry, 2014
Surface modification of zinc oxide on the [Ni 4 Al(OH) 10 ]OH has been performed by a chemical surface precipitation method. Inductively coupled plasma measurements show that the amount of ZnO of prepared samples increases with the increase of initial concentration of Zn 2+ in the mother solution. Powder X-ray diffraction measurements and scanning electron microscope images show that the modification of ZnO has little effects on the lattice parameters and the particle sizes of the [Ni 4 Al(OH) 10 ]OH, but does change the morphology. The charge-discharge cycles results show that the deterioration rate of discharge capacity for the electrode with ZnO is only 4.0 % after 255 cycles, which is lower than that of electrode without ZnO (8.5 %); meanwhile, the maximal numbers of exchanged electrons per nickel atom for the electrodes with ZnO are basically over 1.83, which are higher than that of the electrode without ZnO (1.73), indicating that the modification of ZnO can improve the utilization of active material. In addition, the cyclic voltammogram tests results show that the modification of ZnO not only improves electrochemical cyclic reversibility but also elevates the oxygen evolution potential. Electrochemical impedance spectroscopy measurements show that the modification of ZnO can lower the double layer capacitance and the charge transfer resistance.
Development of lightweight nickel electrodes for zinc/nickel oxide cells
Journal of Power Sources, 1996
... References. ELSEVIER Journal of Power Sources 58 (1996) 9397 J IN L fll U Development of lightweight nickel electrodes for zinc nickel oxide cells Waltraud Taucher *, Thomas C. Adler, Frank R. McLarnon, Elton J. Cairns ... [ 19] D. Coates, G. Paul and P Daugherty, J. Power ...
Electrodeposition of Zinc from Galvanized Steel
Journal of University of Babylon for Engineering Sciences
In this work, the effect of voltage and concentration on the properties of zinc powder (purity, morphology, and apparent density) that produced by electrodeposition process from industrial waste (galvanized steel) was studied. In Electrodeposition process, used sulfuric acid H₂SO₄ with concentration 0.2M and zinc sulphate heptahydrate ZnSO₄.7H₂O in three different concentrations (100, 75, and 50) M, The time of deposition is 10 mins, three electrodes were used, the distance between electrodes was 3cm for all experiments and the PH of solutions were 0.3, 0.4, 0.6 for three concentrations respectively. The voltages that used were (2, 3, 4, 6, 8, and11) V. First of all, the morphology of zinc powder for all experiments was dendritic. The effect of voltage on the apparent density in ranging was from 1.2 to 0.71 gm. /cm3 in 100M for voltages from 2V to 11V, it was from 0.94 to0.60 gm. /cm3 in 75M, and it was from 0.80 to 0.50 gm. /cm3 in 50M concentration. The purities increased with dec...
Materials Chemistry and Physics, 2011
The electrodeposition of Zn-Ni-Co alloys from sulphate electrolytes was studied on steel rod. In order to elucidate the characteristics of the layer formation, a complementary approach was used based on the combination of various electrochemical techniques. The cyclic voltammetry and galvanostatic techniques for electrodeposition, while potentiodynamic polarization resistance and anodic linear sweeping voltammetry techniques were used for corrosion study. Under the examined conditions, electrochemical and surface analysis indicate that the deposition has taken place with the formation of three structures have a composition corresponding to pure Zn, ␥-Ni 5 Zn 21 and pure Co phases. The influence of nickel concentration as well as the effect of potential on the surface appearance and the deposits composition was examined. Under these experimental conditions the electrodeposition of the alloys is of anomalous type. The results indicate that the addition of Ni to the Zn-Co alloy, Zn-Ni-Co alloy formed which is more corrosion resistance than Zn-Co alloy. Also, the amount of ␥-phase increased and the amount of pure Zn decreased with the increase of nickel concentration in the bath. The corrosion resistance of the zinc-nickel-cobalt alloy had been improved with the more concentration of nickel. The Ni content in the deposition layer had been increased at high deposition potential, whereas, pure Zn deposition had been decreased.
Zn-Ni electrodeposition for enhanced corrosion performance
Zinc-Nickel (Zn-Ni) electrodeposition has been carried out using direct current. Cathode current efficiency and deposit thickness were determined by weight measurement method. Influence of current density on the deposition process was also investigated. The morphologies of the deposits were studied using Scanning Electron Microscope and Field Emission Gun Scanning Electron Microscopes. Effect of temperature on the Ni content and morphologies of the deposits was also studied. Energy dispersive spectroscopy (EDX) was utilised to analyse the elemental composition of the deposits. It was found that temperature changes in the bath had a marked influence on the Ni content and morphology of the deposits. Deposit surface profile revealed non-uniform distribution of Ni in the deposits. Anomalous deposition behaviour was exhibited by the baths and Ni content of 10-15wt% for best corrosion performance was obtained between 60-75 g/l of NiCl 2 .6H 2 O. Normal deposition took place at current densities lower than 2A/dm 2 . Deposits with 12wt% Ni exhibited best corrosion performance.
Fabrication and Investigation of the Charge/Discharge Characteristics of Zinc
2007
Electrochemical properties of a zinc/polyvinyl alcohol-potassium hydroxide/carbon cell have been investigated. In this cell, PVA-KOH gel has been used as an electrolyte with PVA/KOH wt.% ratio of 60:40, while zinc and carbon rods served as electrodes. The cylindrical glass vessel of length 3.0 cm and of diameter 2.0 cm has been used as a cell compartment. The current-voltage characteristics and open circuit voltage-time, charge voltage/current-time and discharge voltage/current-time studies have been done. The open circuit voltage has been observed for 160 h. It has been found that the cell shows stability and is rechargeable, too.
Journal of Solid State Electrochemistry, 2002
The corrosion and passivation of Zn powder particles dispersed in a paste electrode immersed in 0.5 M Na 2 SO 4 and 5´10 ±3 M Na 2 HPO 4 solutions were studied mainly by electrochemical impedance spectroscopy. The role played by diusion in the mechanism of anodic oxidation of zinc powder particles has been shown. It was demonstrated that the anodic reactionof Zn powder in neutral or near neutral media involves at least two adsorbed intermediates. By simulating the porous structure of the electrode, some information about porous nature of zinc electrode could be extracted.
Journal of Power Sources, 2012
The electrodeposition of galvanic coatings was performed using a chloride-based acidic electrolytic bath containing polyethylene glycol (PEG) as an additive. The electrolytic bath was prepared using Zn and Mn recovered from exhausted zinc-carbon batteries by means of acid leaching with HCl. The coatings were obtained potentiostatically at −1.2 V and −1.6 V (vs. Ag/AgCl) and galvanostatically with a current density of −10 mA cm −2 . The results indicated that the presence of PEG in the bath during galvanostatic deposition favored the formation of a coating containing a mixture of Zn and Zn-Mn alloy with an Mn content of around 2 wt%.
Materials Chemistry and Physics, 2008
Zinc powder, as active material of secondary alkaline zinc electrode, can greatly limit the performance of zinc electrode due to corrosion and dendritic growth of zinc resulting in great capacity-loss and short cycle life of the electrode. This work is devoted to modification study of zinc powder with neodymium conversion films coated directly onto it using ultrasonic immersion method for properties improvement of zinc electrodes. Scanning electron microscopy and other characterization techniques are applied to prove that neodymium conversion layers are distributing on the surface of modified zinc powder. The electrochemical performance of zinc electrodes made of such modified zinc powder is investigated through potentiodynamic polarization, potentiostatic polarization and cyclic voltammetry. The neodymium conversion films are found to have a significant effect on inhibition corrosion capability of zinc electrode in a beneficial way. It is also confirmed that the neodymium conversion coatings can obviously suppress dendritic growth of zinc electrode, which is attributed to the amelioration of deposition state of zinc. Moreover, the results of cyclic voltammetry reveal that surface modification of zinc powder enhances the cycle performance of the electrode mainly because the neodymium conversion films decrease the amounts of ZnO or Zn(OH) 2 dissolved in the electrolyte.