It was proposed to study the influence of various carbon
powders added to MnO2cathode on the discharge capacity
of the MnO2
-Zn test cells. Hence, a cathode-limited cell
with excess zinc anode was fabricated, with a provision to
measure simultaneously cathode potential and cell potential
during the cell discharge measurements. Figure1shows the
construction of the cell used in our study. A zinc can with
inner dimension 4.5 cm * 0.3 cm (diameter * height) and an
active surface area of 20 cm
2
, approximately equivalent to
inner area of R6cell (or AA cell), was placed at the bottom
of an acrylic cylinder, and a polypropylene separator was
placed above that. Cathode paste was prepared by mixing
electrolytic manganese dioxide with the selected carbon
powder in 10:1w/wratio [1, 10] wetted with 30% zinc
chloride electrolyte and was placed above the separator
(saturated with electrolyte). A graphite disc of 20-cm
2
area
was placed above the cathode mix, and a uniform load was
applied. An Ag/AgCl reference electrode was inserted into
the cathode mix to measure the potential.