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Abstract: RuO2-based electrodes are generally known to be unstable for O2 evolution. In this paper, a stable type of RuO2-based electrode, Ti/RuO2–Sb2O5–SnO2, is demonstrated for O2 evolution. In the ternary oxide coating, RuO2 serves as the catalyst, SnO2 as the dispersing agent, and Sb2O5 as the dopant. The accelerated life test showed that the Ti/RuO2–Sb2O5–SnO2 electrode containing 12.2molar percent of RuO2 nominally in the coating had a service life of 307h in 3M H2SO4 solution under a current density of 0.5Acm−2 at 25°C, which is more than 15 times longer than other types of RuO2-based electrodes. Instrumental analysis indicated that RuO2–Sb2O5–SnO2 was a solid solution with a compact structure, which contributed to the stable nature of the electrode. [Copyright &y& Elsevier]

Abstract: The stability of one material, Ti/Cu x Co3−x O4, as anode and also cathode was investigated for electrolysis of alkaline aqueous solution. The electrodes were prepared by thermal decomposition method with x varied from 0 to 1.5. The accelerated life test illustrated that the electrodes with x =0.3 nominally showed the best performance, with a total service life of 1080h recorded in 1M NaOH solution under alternating current direction at 1Acm−2 and 35°C. The effects of copper content in electrode coating were examined in terms of electrode stability, surface morphology, coating resistivity and coating compositions. The presence of Cu in the spinel structure of Co3O4 could significantly enhance the electrochemical and physicochemical properties. The trends of crystallographic properties and surface morphology have been analyzed systemically before, during and after the electrodes were employed in alkaline electrolysis. The oxygen evolution would lead to the consumption of the coating material and the progressive cracking of the coating. Along with hydrogen evolution, cobalt oxide could be reduced to metal Co and Co(OH)2 with particle sizes changed to smaller values in crystal and/or amorphous form at the cathode. The formation of Co is the key process for this electrode to serve as both anode and cathode. It is also the main reason leading to the eventual failure of the electrodes. [ABSTRACT FROM AUTHOR]

Abstract: Monodispersed hollow Fe3O4 spheres with different diameters and shell thickness were synthesized by a simple solvothermal process and were investigated as anode materials for lithium ion batteries (LIBs). The shell of the hollow spheres exhibited porous structure composed of aggregated Fe3O4 nanoparticles. The composition and morphology of the obtained samples were characterized by X-ray powder diffraction (XRD), Raman spectra, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A novel formation mechanism was proposed based on the results of time-dependent reactions. The electrochemical tests of the hollow Fe3O4 spheres were performed to determine the reversible capacity, rate and cycling performance as anode materials for LIBs. The Fe3O4 obtained from the reaction at 200°C for 48h exhibited the best specific capacity and capacity retention and superior rate performance compared to other Fe3O4 spheres, which is ascribed to their reasonable particle size, high crystallinity and hollow spherical structures. Different conductive additive were used to investigate the electrochemical performance of Fe3O4 hollow spheres. The binary conductive additives containing acetylene black (AB) and carbon nanobutes (CNTs) improved the electrochemical performance of the Fe3O4 hollow spheres obviously. The results reveal that there is a synergistic effect of the particle size, crystallinity and conductive agents on the electrochemical properties of the hollow Fe3O4 spheres. [Copyright &y& Elsevier]