
482 Fuel Cells
For dominant mass concentration loss in the cathode electrode, the limit-
ing current density is given by Equation 11.24b
jnFD
x
L
LeO
eff
cO
c
2
2,ch
=
ρ
.
(11.24b)
Example 11.3: One-Dimensional SOFC Model
Consider the electrolyte as 8% YSZ solid oxide fuel cell with the follow-
ing known data:
Anode gas stream:
Inlet gas composition: 95% H
2
and 5%H
2
O
Inlet pressure, P
a
= 1 atm (101.3 Pa)
Cathode gas stream:
Inlet gas composition: Air with 21% O
2
and 79% N
2
Inlet pressure, P
c
= 1 atm (101.3 Pa)
Diffusivities:
H
2,
H
2
2,
N
2
eff2ef
m/sand cm /s=× =
−
11
2
4
.
Kinetic parameters:
Cathode exchange transfer coefcient, α = 0.5
Cathode exchange curre ...