Oxidation States in Layered Nickel Oxide Based Electrode Materials

1992 ◽  
Vol 293 ◽  
Author(s):  
Claude Delmas
Keyword(s):  
Electrode Materials ◽  
Ligand Field ◽  
Spin Configuration ◽  
Nickel Ions ◽  
Cobalt Ions ◽  
Cationic Distribution ◽  
Cobalt Substitution ◽  
Electrochemical Cycling ◽  
Iron Nickel ◽  
Structural Parts

AbstractNiO2 slabs made of edge-sharing NiO6 octahedra are the main structural parts of the positive electrode materials involved in Ni-Cd, Ni-M- and Li-LiNiO2 secondary batteries. These electrochemical systems are among the best ones for applications. The behavior of all these electrode materials can be optimized by substituting several cations for nickel.The effect of iron and cobalt substitution has been investigated in detail. The oxidation state modifications resulting from the electrochemical cycling have been characterized from magnetic, conductivity, thermoelectric-power and Mössbauer studies. The overall results show that nickel ions are oxidized to the tetravalent state before cobalt ions. More surprisingly, the oxidation of iron-nickel mixed phases shows the simultaneous presence of tetravalent iron and nickel ions in the low spin configuration. For the first time, in situ M6ssbauer measurements have been performed during the cycling of a nickel-cadmium cell.This cationic distribution results from the competition between the intrinsic redox properties of the 3d cations and the accommodation of the oxidation levels to the ligand field imposed by the prevailing cation.

The Binding and Viscometric Studies of Ni+2, Co+2 and Mn+2 Ions with Protein by Spectrometric and pH Metric Techniques

2019 ◽  
Vol 9 (2) ◽  
pp. 151-162
Author(s):  
Shveta Acharya ◽  
Arun Kumar Sharma
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Protein Molecule ◽  
Vital Role ◽  
Sufficient Evidence ◽  
Structural Requirement ◽  
Nickel Ions ◽  
Cobalt Ions ◽  
Lower Temperature ◽  
Specific Oxidation

Background: The metal ions play a vital role in a large number of widely differing biological processes. Some of these processes are quite specific in their metal ion requirements. In that only certain metal ions, in specific oxidation states, can full fill the necessary catalytic or structural requirement, while other processes are much less specific. Objective: In this paper we report the binding of Mn (II), Ni (II) and Co (II) with albumin are reported employing spectrophotometric and pH metric method. In order to distinguish between ionic and colloidal linking, the binding of metal by using pH metric and viscometric methods and the result are discussed in terms of electrovalent and coordinate bonding. Methods: The binding of Ni+2, Co+2 and Mn+2 ions have been studied with egg protein at different pH values and temperatures by the spectrometric technique. Results: The binding data were found to be pH and temperature dependent. The intrinsic association constants (k) and the number of binding sites (n) were calculated from Scatchard plots and found to be at the maximum at lower pH and at lower temperatures. Therefore, a lower temperature and lower pH offered more sites in the protein molecule for interaction with these metal ions. Statistical effects seem to be more significant at lower Ni+2, Co+2 and Mn+2 ions concentrations, while at higher concentrations electrostatic effects and heterogeneity of sites are more significant. Conclusion: The pH metric as well as viscometric data provided sufficient evidence about the linking of cobalt, nickel and manganese ions with the nitrogen groups of albumin. From the nature and height of curves in the three cases it may be concluded that nickel ions bound strongly while the cobalt ions bound weakly.

Real-time monitoring of stress development during electrochemical cycling of electrode materials for Li-ion batteries: overview and perspectives

2019 ◽  
Vol 7 (41) ◽  
pp. 23679-23726 ◽  
Author(s):  
Manoj K. Jangid ◽  
Amartya Mukhopadhyay
Keyword(s):  
Real Time ◽  
Electrode Materials ◽  
Electrochemical Potential ◽  
Li Ion Batteries ◽  
Stress Development ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Real Time Information ◽  
Time Information

Monitoring stress development in electrodes in-situ provides a host of real-time information on electro-chemo-mechanical aspects as functions of SOC and electrochemical potential.

scholarly journals Properties of Cobalt- and Nickel-Doped Zif-8 Framework Materials and Their Application in Heavy-Metal Removal from Wastewater

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1636
Author(s):  
Bowen Shen ◽  
Bixuan Wang ◽  
Liying Zhu ◽  
Ling Jiang
Keyword(s):  
Heavy Metal ◽  
Metal Removal ◽  
Copper Ions ◽  
Heavy Metal Removal ◽  
Nickel Ions ◽  
Cobalt Ions ◽  
Framework Materials ◽  
Metal Treatment ◽  
Dichromate Ions ◽  
Cobalt And Nickel

Heterometallic zeolite imidazole framework materials (ZIF) exhibit highly attractive properties and have drawn increased attention. In this study, a petal-like zinc based ZIF-8 crystal and materials doped with cobalt and nickel ions were efficiently prepared in an aqueous solution at room temperature. It was observed that doped cobalt and nickel had obviously different effects on the morphology of ZIF-8. Cobalt ions were beneficial for the formation of ZIF-8, while addition of nickel ions tended to destroy the original configuration. Then we compared the absorption ability for metal ions between petal-like ZIF-8 and its doped derivatives with anion dichromate ions (Cr2O72−) and cation copper ions (Cu2+) as the absorbates. Results indicated that saturated adsorption capacities of Co@ZIF-8 and Ni@ZIF-8 for Cr2O72− reach 43.00 and 51.60 mg/g, while they are 1191.67 and 1066.67 mg/g for Cu2+, respectively, which are much higher than the original ZIF-8 materials. Furthermore, both the heterometallic ZIF-8 materials show fast adsorption kinetics to reach adsorption equilibrium. Therefore, petal-like ZIF-8 with doped ions can be produced through a facile method and can be an excellent candidate for further applications in heavy-metal treatment.

In situ Raman and UV-Vis spectroscopic analysis of lithium-ion batteries

2015 ◽  
Vol 1773 ◽  
pp. 33-40 ◽  
Author(s):  
Marcel Heber ◽  
Christian Schilling ◽  
Toni Gross ◽  
Christian Hess
Keyword(s):  
Lithium Ion Batteries ◽  
Spectroscopic Analysis ◽  
Electrode Materials ◽  
Lithium Ion ◽  
In Situ Raman ◽  
Spatially Resolved ◽  
Conductive Additives ◽  
Electrochemical Cycling ◽  
Carbon Based

ABSTRACTThe potential of Raman and UV-Vis diagnostics for spatially-resolved and in situ diagnostics of lithium-ion batteries is demonstrated. Regarding the use of in situ Raman diagnostics focus is put on LiCoO2 electrode materials, which were investigated in detail as composites of LiCoO2 with binder and conductive additives. The potential of in situ UV-Vis analysis is illustrated for carbon-based materials showing significant absorption changes during electrochemical cycling due to lithium de-/intercalation.

scholarly journals Synthesis and Characterization of Black CoFe2O4 Pigments Using MOOH (M = Fe and Co) Nanorod

2017 ◽  
Vol 62 (2) ◽  
pp. 1231-1234
Author(s):  
R. Yu ◽  
J. Yun ◽  
Y. Kim
Keyword(s):  
Solution Method ◽  
One Dimension ◽  
X Ray Diffraction ◽  
Substitution Method ◽  
Cobalt Ions ◽  
X Ray ◽  
Tetrahedral Sites ◽  
Cobalt Substitution ◽  
Divalent Cobalt

AbstractWe studied the coloration and phase transformation of various iron based pigment with cobalt substitution method and heat treatment. First, we synthesized well defined one dimensionβ-Fe/CoOOH nanorods using the solid solution method. Yellowishβ-Fe/CoOOH nanorods were transformed into reddish intermediate states and, finally, black CoFe2O4pigments was obtained. Divalent cobalt ions easily occupied tetrahedral sites. The prepared pigments were well characterized in terms of physical properties by using UV-vis, CIELabcolor parameter measurements, SEM (scanning electron microscopy) and XRD (powder X-ray diffraction). In addition, the magnetization property of the prepared CoFe2O4pigment was confirmed by VSM (vibrating sample magnetometer).

A study on cobalt substitution in sodium manganese mixed-anion phosphates as positive electrode materials for Na-ion batteries

2019 ◽  
Vol 444 ◽  
pp. 227274
Author(s):  
Soojy Ryu ◽  
Ji Eun Wang ◽  
Joo-Hyung Kim ◽  
Riccardo Ruffo ◽  
Young Hwa Jung ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Positive Electrode ◽  
Cobalt Substitution ◽  
Positive Electrode Materials
Sign in / Sign up

Export Citation Format

Share Document