The instrumentation for digitally driven electrochemical experiments
has been developed. Software has been written for experimental control
and high speed data aquisition. The digital control methods were successfully
used in the study of the electrochemistry of the porous lead electrode (the
lead-acid battery negative plate), over an extended temperature range. The
effects of a number of commercially pertenent additives have been studied
at reduced temperatures. These reaction enhancing materials (expanders)
have been studied in detail on both planar and porous lead electrode in
sulphuric acid in the range 1M to 5M.
Deductions concerning the energetics of the reactions have been made
from experimental results. The modes of action of certain expanders are
It was concluded that on the plane lead surface solution phase expander
materials modify the mechanism of the lead sulphate electrocrystallisation -
the current limiting reaction. This was an effect on the solid state process
although a solution Pb2+ process was identified (for the first time) in
battery strength acid.
Electrode incorporated organic expander materials act by modifying
pore geometies and reaction penetration depths. The current transients
due to electrocrystallization in porous lead are very complex and require
very sophisticated modelling techniques to provide a useful fit.
Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.