Solutions to exercises
287
We observe that the smallest capacity is that of the sodium electrode.
Consequently, the capacity of the battery is
Q
C
A h
964 800
268
=
=
Solution 5.15 – General information on fuel cells
1. A solid-electrolyte fuel cell is an energy-conversion system that involves
an electrochemical chain where the oxidizing agent (oxidant) is reduced at
the cathode and a fuel (reducer) is oxidized at the anode. The cathode and
anode are separated by a purely-ionic-conducting solid electrolyte (polymer, ceramic, glass) that seals and isolates the separate anodic and cathodic
compartments.
2. Examples of solid electrolyte fuel cells
2 Example of a solid oxide electrolyte fuel cell
Currently, the most mature solid oxide electrolyte fuel cell (SOFC) uses
the following electrochemical chain:
O 2 ,LSM / YSZ / Ni-YSZ,H 2
The combustion agent is the oxygen in air. LSM is the cathode material. It is
a solid solution based on oxides with the general formula La 1−x Sr x MnO 3−δ .
YSZ forms the solid electrolyte. This is yttria-stabilized zirconia with the
formula (ZrO 2 ) 0.91 (Y 2 O 3 ) 0.09 . The current transport is implemented by the
oxide ion via a vacancy mechanism.
The anode material consists of a composite cermet, where the ceramic is
yttria-stabilized zirconia and the metal is nickel. This material is called
cermet Ni-YSZ. It generally consists of 40 vol% of metallic nickel and
has a porosity on the order of 30%. H 2 is the fuel. It must be free of sulfur
compounds, which poison the anode.
The fuel cell operates in this configuration from 600 to 1 000 °C.
2 Example of a solid polymer-electrolyte fuel cell
The proton exchange membrane fuel cell (PEMFC) that currently offers
the highest performance uses the following electrochemical chain:
O 2 ,Pt / Nafion / Pt,H 2
The electrode materials are composed of platinum particles deposited on
a carbon substrate and that act as catalyst.
287
We observe that the smallest capacity is that of the sodium electrode.
Consequently, the capacity of the battery is
Q
C
A h
964 800
268
=
=
Solution 5.15 – General information on fuel cells
1. A solid-electrolyte fuel cell is an energy-conversion system that involves
an electrochemical chain where the oxidizing agent (oxidant) is reduced at
the cathode and a fuel (reducer) is oxidized at the anode. The cathode and
anode are separated by a purely-ionic-conducting solid electrolyte (polymer, ceramic, glass) that seals and isolates the separate anodic and cathodic
compartments.
2. Examples of solid electrolyte fuel cells
2 Example of a solid oxide electrolyte fuel cell
Currently, the most mature solid oxide electrolyte fuel cell (SOFC) uses
the following electrochemical chain:
O 2 ,LSM / YSZ / Ni-YSZ,H 2
The combustion agent is the oxygen in air. LSM is the cathode material. It is
a solid solution based on oxides with the general formula La 1−x Sr x MnO 3−δ .
YSZ forms the solid electrolyte. This is yttria-stabilized zirconia with the
formula (ZrO 2 ) 0.91 (Y 2 O 3 ) 0.09 . The current transport is implemented by the
oxide ion via a vacancy mechanism.
The anode material consists of a composite cermet, where the ceramic is
yttria-stabilized zirconia and the metal is nickel. This material is called
cermet Ni-YSZ. It generally consists of 40 vol% of metallic nickel and
has a porosity on the order of 30%. H 2 is the fuel. It must be free of sulfur
compounds, which poison the anode.
The fuel cell operates in this configuration from 600 to 1 000 °C.
2 Example of a solid polymer-electrolyte fuel cell
The proton exchange membrane fuel cell (PEMFC) that currently offers
the highest performance uses the following electrochemical chain:
O 2 ,Pt / Nafion / Pt,H 2
The electrode materials are composed of platinum particles deposited on
a carbon substrate and that act as catalyst.