Search

The precise observation of a solid–liquid interface by means of frequency modulation atomic force microscopy (FM-AFM) was performed, demonstrating its applicability to a study on lead acid batteries using an electrochemical test cell for in-liquid FM-AFM embedded with a specialized cantilever holder. The consistency and reproducibility of each surface profile observed via amplitude modulation AFM and FM-AFM were verified properly in a strong acidic electrolyte. In terms of FM-AFM, the ability to observe remarkable changes in the force mapping is the most beneficial, especially near the negative electrode surface. The localization of lignosulfonate (LS) added into the electrolyte as an expander could be visualized since this characteristic force mapping was captured when LS was added to electrolyte. [ABSTRACT FROM AUTHOR]

Abstract: The effect of lignosulfonate (LS) on electrochemical reaction of lead electrode (as a model of negative electrode) has been investigated in 1M, 3M, or 7.1M H2SO4 aqueous solution with 0, 10, 100 or 1000mgl−1 of LS using cyclic voltammetry (CV) combined with in situ electrochemical atomic force microscopy (EC-AFM), as well as rotating ring disk electrode (RRDE). The anodic peaks of the CVs, which correspond to overall reaction of , shifted positive when LS was added or the concentration of H2SO4 was lower. The anodic capacities of the CVs increased with addition of LS when the concentration of H2SO4 was lower. When LS was added, the anodic capacities of the CVs usually increased especially in less concentrated H2SO4 solution at higher sweep rate, while the anodic capacity slightly decreased in 7.1M H2SO4 solution with addition of LS at sweep rate of 10mVmin−1; that is, in most concentrated H2SO4 solution at lower sweep rate in this paper. Two cathodic peaks of the CVs were observed when LS was added, and the peak at lower potential shifted more negative with increase of LS. Lead sulfate crystals dissolved at more negative potential with increase of LS. LS up-took Pb2+ ions in H2SO4 aqueous solution during discharging. [Copyright &y& Elsevier]

The decay of nano-islands on the surface of a Au(111) electrode, in contact with 50 mM sulfuric acid aqueous solution under an applied potential in the range of 0.15–1.2 V, has been investigated using electrochemical atomic force microscopy (EC-AFM). The results are compared with those previously obtained for Au(100). With either orientation, it is found that the area of the top layer of multi-layered islands decreases linearly with time at any applied potential. It was also found that the decay rate, defined as the rate of decrease of the number of atoms in the top-layer of the islands per second, increases with the magnitude of the applied potential. Further, the decay rate of the top layer of the islands on Au(111) is almost the same as that on Au(100). [Copyright &y& Elsevier]

Pb(1 0 0) and Pb(1 1 1) single crystals in 50 mM H2SO4 aqueous solution have been investigated by in situ electrochemical atomic force microscopy (EC-AFM) under potential control. We have succeeded in observating high resolution images of Pb(1 0 0) and Pb(1 1 1) single crystals, as well as high resolution and morphological images of PbSO4 crystals formed on the Pb single crystals. We found that the top face of PbSO4 crystals formed on Pb(1 0 0) is PbSO4(0 0 1), while that on Pb(1 1 1) is PbSO4(1 0 0). We also found that the atomic rows along the [1 0 0] and [0 1 0] direction of PbSO4(0 0 1) surface were parallel with those along the [0 1 1] and [0 1 1¯] direction of the Pb(1 0 0) substrate, while those along the [0 1 0] and [0 0 1] direction of the PbSO4 (1 0 0) surface were parallel with those along the [0 1 1¯] and [1¯ 1 1] direction of the Pb(1 1 1) substrate. [Copyright &y& Elsevier]