The Electrochemical Activity of PbO2 : A Nuclear Magnetic Resonance Study of Hydrogen in Battery and Chemically Prepared Material

Abstract

Solid-state magic-angle-spinning nuclear magnetic resonance studies have been undertaken on positive plate material from lead-acid batteries and on samples of both pure ~-PbO2 and pure ~-PbO~ prepared by nonelectrochemical methods. Battery positive plate samples contain protons in two different surface and near surface configurations. One of these proton species is associated with mobile, isolated, adsorbed hydroxyl groups, and/or water molecules that can be removed by outgassing. The other proton species is not removed by outgassing; it probably corresponds to water molecules and/or closely spaced hydroxyl groups trapped on internal crystal surfaces. The proton species present in fresh (uncycled) positive plate material are not significantly different in either configuration or abundance from those in extensively cycled samples. Thus, it is unlikely that decline in battery capacity with cycling service is associated with a change in the hydrogen content of PbO2. Chemically prepared varieties of ~-PbO2 and ~-PbO2 are each different from their electrolytically formed counterparts in terms of both the abundance and the nature of the proton species on or near their surfaces; these differences can be related to differences in the manner of their preparation. With the possible exception of chemical ~-PbO2, none of the samples of PbO2 contain protons in configurations attributable to strongly bound, structural hydroxyl groups, as occur in the stoichiometric phase Pb302(OH)2.The role of hydrogen.--The lead-acid battery derives ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 129.173.72.87

Influence of some metal ions on the structure and properties of doped β-PbO2

“…Based on the results of kinetic tests and coulometric data Fitas et al [5] have established that the process of PAM reduction includes two electrochemical stages (one electron is consumed during each stage) taking place in the gel zones according to a proton-electron mechanism or a double-injection process. The role of structural water and H + ions in the reactivity of the positive active mass has been emphasized by different authors [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. It has been established that heat treatment of PAM results in evaporation of water from the hydrated zones and reduces considerably the proton diffusion coefficient, thus reducing the discharge capacity of the plate.…”