High efficiency of the lead methanesulfonate flow battery achieved by changing the characteristics of PbOx under potentiostatic conditions. (August 2019)

• Record Type: Journal Article
• Authors: Luo, Xiaofei; Liu, Zheng; Jiang, Bailing; Ji, Dongdong
• Is Part Of: Journal of energy storage. Volume 24(2019)
• Publication Date: 2019-08
• Subjects: Lead methanesulfonate flow battery -- Potentiostatic conditions -- Impedance -- Coulombic efficiency; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2019.100771
• Languages: English
• ISSNs: 2352-152X

Abstract

Graphical abstract: Highlights: The chemical state of PbOx varies with the positive electrode potential. The size and distribution of PbOx particles are smaller and narrower at high positive electrode potential. The high coulombic efficiency of cycles is achieved by controlling the cell voltage. Abstract: To investigate the deposition and dissolution of the anodic deposited materials in the lead methanesulfonate flow battery, phase composition, grain and particle sizes, stoichiometry and conductivity of PbO2 are investigated, which are deposited at different positive electrode potentials. ΩWith the positive electrode potential increasing, the content of α-phase increases compared with β-phase's by X-ray diffraction (XRD) analyses. Mean grain sizes are not apparently changed by calculation using Debye-Scherrer formula. But the particle sizes indeed become smaller with the positive electrode potential increasing, which are investigated using scanning electron microscope (SEM). Since the anodic deposited material is the compound in which oxygen deficiency in PbO2, X-ray photoelectron spectroscopy (XPS) is introduced to characterize the non-stoichiometry of PbO2 deposited at four typical positive electrode potentials, 1.5, 1.7，1.8 and 2.0 V vs. SCE. Here PbOx is utilized to represent this kind of compound. The highest value of x = 1.73 ± 0.03 in PbOx is obtained at 2.0 V vs. SCE, only x = 1.46 ± 0.02 for that electrodeposited at 1.5 V vs. SCE. It is also found that the polarization impedances of working electrodes covered by different PbOx layers decrease with the electrodeposition potential of PbOx increasing, which are 170，37，12 and 2.4 Ω respectively at 1.5, 1.7，1.8 and 2.0 V vs. SCE. By controlling the cell charge voltage of 2.15 V, corresponding to the positive electrode potential of 1.7 V vs. SCE, 261 cycling numbers have been achieved at the discharging current density of 40 mA cm -2 with a coulombic efficiency of more than 80 %.