<s>
A	O
silver	B-Device
oxide	I-Device
battery	I-Device
(	O
IEC	O
code	O
:	O
S	O
)	O
is	O
a	O
primary	B-Algorithm
cell	I-Algorithm
using	O
silver	O
oxide	O
as	O
the	O
cathode	O
material	O
and	O
zinc	B-Application
for	O
the	O
anode	O
.	O
</s>
<s>
They	O
are	O
available	O
in	O
small	O
sizes	O
as	O
button	B-Algorithm
cells	I-Algorithm
,	O
where	O
the	O
amount	O
of	O
silver	O
used	O
is	O
minimal	O
and	O
not	O
a	O
prohibitively	O
expensive	O
contributor	O
to	O
the	O
overall	O
product	O
cost	O
.	O
</s>
<s>
Silver	O
oxide	O
primary	B-Algorithm
batteries	I-Algorithm
account	O
for	O
30%	O
of	O
all	O
primary	B-Algorithm
battery	I-Algorithm
sales	O
in	O
Japan	O
(	O
64	O
out	O
of	O
212	O
million	O
in	O
February	O
2020	O
)	O
.	O
</s>
<s>
Silver	B-Device
oxide	I-Device
batteries	I-Device
were	O
used	O
on	O
Apollo	O
program	O
lunar	O
missions	O
for	O
the	O
lunar	O
module	O
and	O
lunar	O
rover	O
power	O
supplies	O
because	O
of	O
their	O
high	O
energy-to-weight	O
ratio	O
.	O
</s>
<s>
A	O
silver	B-Device
oxide	I-Device
battery	I-Device
uses	O
silver(I )	O
oxide	O
as	O
the	O
positive	O
electrode	O
(	O
cathode	O
)	O
,	O
zinc	B-Application
as	O
the	O
negative	O
electrode	O
(	O
anode	O
)	O
,	O
plus	O
an	O
alkaline	O
electrolyte	O
,	O
usually	O
sodium	O
hydroxide	O
(	O
NaOH	O
)	O
or	O
potassium	O
hydroxide	O
(	O
KOH	O
)	O
.	O
</s>
<s>
The	O
silver	O
is	O
reduced	O
at	O
the	O
cathode	O
from	O
Ag(I )	O
to	O
Ag	O
,	O
and	O
the	O
zinc	B-Application
is	O
oxidized	O
from	O
Zn	O
to	O
Zn(II )	O
.	O
</s>
<s>
 { Zn } 	O
+	O
2OH^	O
-	O
->	O
\overset{Zinc~hydroxide}{Zn( OH	O
)	O
2}	O
+	O
2e-	O
,	O
</s>
<s>
Until	O
recently	O
,	O
all	O
silver	B-Device
oxide	I-Device
batteries	I-Device
contained	O
up	O
to	O
0.2	O
%	O
mercury	O
.	O
</s>
<s>
The	O
mercury	O
was	O
incorporated	O
into	O
the	O
zinc	B-Application
anode	O
to	O
inhibit	O
its	O
continuous	O
corrosion	O
in	O
the	O
alkaline	O
environment	O
,	O
which	O
would	O
otherwise	O
occur	O
regardless	O
of	O
whether	O
or	O
not	O
the	O
battery	O
was	O
providing	O
power	O
.	O
</s>
<s>
Sony	O
started	O
producing	O
the	O
first	O
silver	B-Device
oxide	I-Device
batteries	I-Device
without	O
added	O
mercury	O
in	O
2004	O
.	O
</s>
