Influence of the Memory Effect on X-ray Photoelectron Spectroscopy and Raman Scattering in Positive Electrode of Ni-MH Batteries

Abstract

The influence of the memory effect on X-ray diffraction, X-ray photoelectron spectroscopy and Raman scattering in the positive electrodes of the nickel metal hydride batteries were investigated. The obtained data of X-ray diffraction, X-ray photoelectron spectroscopy and Raman scattering in the samples shown the memory effect are hardly affected during the charge-discharge processes. The peak intensity of the Raman mode due to the defect of the crystal structure in the samples shown the memory effect is larger than those in the normal and reconditioned samples. These results suggest that the samples shown the memory effect involve more disorder and/or proton vacancy than the normal and reconditioned samples. Consequently, the redox mechanism of the nickel oxide electrode based on the reversible insertion-deinsertion of protons and electrons is deteriorated.

Capacity Degradation Mechanisms in Nickel/Metal Hydride Batteries

“…Magnetic susceptibility (MS) measurements can be used to monitor the evolution of the count and size of metallic Ni-clusters embedded in the surface oxide [26,34,35]. Both X-ray photoelectron spectroscopy (XPS) [36][37][38][39][40] and Auger electron spectroscopy (AES) [41] have been used to study the surface composition, with the former being able to identify the oxidation state. The acoustic emission (AE) technique has also been used to study the volume change and pulverization of the MH alloy [42,43].…”

“…Fourier transform infrared spectroscopy (FTIR) has been used to study the OH´ligand in Ni(OH) 2 [44][45][46][47]. Raman spectroscopy (RS) is another optical measurement used to characterize the changes in the separator and positive electrode [37,[46][47][48]. Electrochemical impedance spectroscopy (EIS) or AC impedance measurements are usually used to isolate components with different degrees of degradation [49][50][51][52].…”

Interconnected Ni(HCO3)2 Hollow Spheres Enabled by Self-Sacrificial Templating with Enhanced Lithium Storage Properties

“…For the Ni 2p XPS spectra (Figure 3f), pristine Ni(HCO 3 ) 2 hollow spheres showed a single Ni 2p 3/2 peak at 856.4 eV, while the first charged sample had three Ni 2p 3/2 peaks at 850.4, 856.4, and 858.6 eV, which can be attributed to Ni, Ni 2+ , and Ni 3+ , respectively. 29 For the 10th charged sample, there were only two Ni 2p 3/2 peaks at 850.4 eV (Ni) and 858.8 eV (Ni 3+ ). Overall, the contributions from the further oxidation of Ni 2+ into Ni 3+ and the reversible reactions between HCO 3 − and Li x C 2 (x = 0, 1, or 2) should be invoked to calculate the new theoretical capacity of Ni(HCO 3 ) 2 , yielding 1928 mAh g −1 (n = 13 at x = 2).…”

“…The additional reaction in HCO 3 – could be also proved by the capacity of Ni­(HCO 3 ) 2 being higher than that of NiO hollow spheres at 1000 mA g –1 (Figure S11). For the Ni 2p XPS spectra (Figure f), pristine Ni­(HCO 3 ) 2 hollow spheres showed a single Ni 2p 3/2 peak at 856.4 eV, while the first charged sample had three Ni 2p 3/2 peaks at 850.4, 856.4, and 858.6 eV, which can be attributed to Ni, Ni 2+ , and Ni 3+ , respectively . For the 10th charged sample, there were only two Ni 2p 3/2 peaks at 850.4 eV (Ni) and 858.8 eV (Ni 3+ ).…”

Electroless deposition of RuO2-based nanoparticles for energy conversion applications

“…S4, † which are corresponding to Ni(OH) 2 and NiOOH. 48 Again, this result demonstrates the oxidation of NiCl 2 to form nickel oxyhydroxide and nickel hydroxide. Based on the above preliminary test, this V 4+ -catalyzed electroless deposition presents an enormous potential in transition metal oxide deposition.…”