194
4 – Electrode reactions
R W = 36.65 # π
We find
R
115 cm
W
2
Ω
=
3. For a least squares fit, we use the following form:
Z( ) R
j
tanh j
W
ω
τ ω
τ ω
=
#
where R W and τ are fitting parameters.
By identification, we obtain D
2
τ
δ
=
.
( .
)
D
1 425
0 35 10
4 2
#
=
−
.
D
c m s
8 6 10
10
2 1
#
=
−
−
We deduce the expression for the interface concentration of carriers:
C
R
1
n F
RT D
0
W
2 2
δ
=
#
#
(
)
.
.
.
C
115
1
2 96 480
8 314 698
8 6 10
0 35 10
0
2
1 0
4
#
#
=
−
−
#
#
#
#
C
5.5 10 m l cm
0
5
3
#
ο
=
−
−
4. The ASR is the total resistance of the electrode per unit surface area. The
electrode resistance corresponds to the sum A + R 2 . Because the sample is
symmetric, the resistance of one electrode is half, or
ASR
2
A R S
2
=
+
#
ASR
2
73.3 58.1 π
=
+
#
ASR 206.3 cm
2
Ω
=
Solution 4.3 – Overpotential in an oxygen electrochemical pump
1. Defect responsible for ionic conduction in stabilized zirconia
Schottky disorder is the dominant disorder in zirconia
0 m V
4 ′
Zr + 2V O
::
4 – Electrode reactions
R W = 36.65 # π
We find
R
115 cm
W
2
Ω
=
3. For a least squares fit, we use the following form:
Z( ) R
j
tanh j
W
ω
τ ω
τ ω
=
#
where R W and τ are fitting parameters.
By identification, we obtain D
2
τ
δ
=
.
( .
)
D
1 425
0 35 10
4 2
#
=
−
.
D
c m s
8 6 10
10
2 1
#
=
−
−
We deduce the expression for the interface concentration of carriers:
C
R
1
n F
RT D
0
W
2 2
δ
=
#
#
(
)
.
.
.
C
115
1
2 96 480
8 314 698
8 6 10
0 35 10
0
2
1 0
4
#
#
=
−
−
#
#
#
#
C
5.5 10 m l cm
0
5
3
#
ο
=
−
−
4. The ASR is the total resistance of the electrode per unit surface area. The
electrode resistance corresponds to the sum A + R 2 . Because the sample is
symmetric, the resistance of one electrode is half, or
ASR
2
A R S
2
=
+
#
ASR
2
73.3 58.1 π
=
+
#
ASR 206.3 cm
2
Ω
=
Solution 4.3 – Overpotential in an oxygen electrochemical pump
1. Defect responsible for ionic conduction in stabilized zirconia
Schottky disorder is the dominant disorder in zirconia
0 m V
4 ′
Zr + 2V O
::