1070-4272/02/7507-1091$27.00C2002 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 75, No. 7, 2002, pp. 1091!1094. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 7,
2002, pp. 1108!1111.
Original Russian Text Copyright + 2002 by Kolikova, Barsukova.
AND CORROSION PROTECTION OF METALS
A Possibility of Improving Lead Dioxide Electrode
of Lead Battery
G. A. Kolikova and M. M. Barsukova
Istochnik Research Institute of Batteries, Joint-Stock Company, St. Petersburg, Russia
Received January 8, 2002
Abstract-The influence exerted by a reinforcing additive, an aqueous suspension of 4D fluoroplastic (Tef-
lon), on the structural, physicochemical, and service characteristics of the positive electrode of the lead battery
was studied. A paste with polymer and carbon additives, extending the service life of the lead dioxide elec-
trode, was developed for industrial use.
Presently, lead batteries constitute about 85% of
the entire amount of chemical power cells, and, there-
fore, further improvement of their service characteris-
tics remains a topical task. One of the most important
service characteristics of a lead battery is its service
life, which largely depends on the service life of the
positive electrode. The failure of a positive electrode
is mainly due to corrosion of current leads (grids) and
sagging of the active paste, with the shares of these
factors being approximately equal.
The problems and methods of improvement of the
positive electrode in a lead acid battery were reviewed
in considerable detail in . An analysis of the causes
and mechanisms of disintegration of the active paste
in the lead dioxide electrode revealed their fundamen-
tal nature, much hindering the possibility of eliminat-
ing this phenomenon .
One of ways to extend the service life of lead bat-
teries is to use as a binder in the positive active paste
an aqueous suspension of 4D fluoroplastic (Teflon)
(VSF4D) . This additive shows high chemical sta-
bility with respect to sulfuric acid and resistance to
electrochemical oxidation at high anode potentials,
which occur at the positive electrode.
However, despite the positive effect of this additive
on the service life of lead batteries, it has not found
practical use. The reason is that the results obtained
are inadequate since no systematic study of the influ-
ence exerted by the VSF4D additive on the electrical
and physicochemical properties of the lead dioxide
electrode has been performed; furthermore, the addi-
tive exerts a negative effect on the application charac-
teristics of the paste and the formation process.
To solve these problems, we examined in this work
the influence exerted by the VSF4D additive on the
structural, physicochemical, and service characteristics
of the lead dioxide electrode.
The aqueous suspension of 4D fluoroplastic con-
tained fluoroplastic particles 0.3 mm in diameter,
which are in the suspended state because of the addi-
tion of a surfactant, have a spherical shape, and are
stretched into elastic fibers under mechanical action
(in the process of application). The content of fluoro-
plastic in the suspension is 50360 wt %. In accor-
dance with the technology developed, the amount of
VSF4D introduced into the paste is 0.0530.15% (in
terms of dry substance). Simultaneously, one more
additive, a carbon-chain polymeric fiber, can be intro-
duced into the paste in amount of 0.013 0.4 wt % to
enhance its strength in electrode fabrication .
The present study is concerned with the effect of
the reinforcing VSF4D additive and Khlorin fiber on
the structure of the positive active paste (porosity,
pore tortuosity factor), electrical resistance, and capac-
ity characteristics of the electrode in various modes of
its discharge and on its service life.
The study was carried out on electrodes of the MT
type with the dimensions 62 0 74 0 2.65 mm. Current
leads were fabricated from a lead3antimony alloy with
antimony content of 6 wt %; the mass of the leads was
35+ 1 g. Positive pastes were prepared from powdered
lead produced with a Chloride mill (PbO content
68.4%, moisture capacity 136 ml kg
, apparent den-
sity 1.48 g cm
) and sulfuric acid with addition of