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Carbon, platinum and lead microelectrodes have been used to study electrocrystallization reactions relevant to lead-acid battery electrochemistry. It is shown that single centres of α- and β-PbO 2 can be formed on carbon fibre microdisc electrodes, allowing direct measurement of the kinetics of phase growth in the absence of overlap. The validity of the analysis of current time transients has been established by examining the number, shape and size of the growth centres by scanning electron microscopy. At the same time, it has been found that the morphology of single centres of the two phases is quite different. The reductive transformation of individual α- and βPbO 2 centres to PbSO 4 has been studied as a function of sulphuric acid concentration by scanning electron microscopy, and the interconversion of lead, lead sulphate and lead dioxide has also been investigated using lead microdisc electrodes. The combination of kinetic and electron microscopic measurements at microelectrodes has revealed details of the reaction mechanisms that cannot be derived from observations at electrodes of conventional size.

It is shown that the use of carbon microdisc electrodes allows the study of the nucleation and growth of single centres of α-PbO2 at high overpotentials. The simplicity of the analysis of the arrival time distributions in such experiments is contrasted with the difficulties in interpretation of the non-steady-state of nucleation on electrodes of conventional size. In restricted ranges of overpotential, the formation of nuclei can be explained in terms of pure birth processes and the kinetics of lattice formation can then be derived at the molecular level.

Mercury ultramicroelectrodes have been prepared by the electrodeposition of mercury on 0.6 μ platinum microdiscs. The electrodes have been used for the determination of soluble Pb(II) in sulphuric acid solutions and for in-situ measurements in the lead acid battery. The results show that the ultra-microelectrodes offer a simple and reliable method of probing the solution composition under conditions where large area electrodes cannot be used.