This document summarizes a seminar presentation about fuel cells. It begins with an introduction that defines fuel cells and batteries. It then describes the basic components and chemical reactions of different types of fuel cells, including hydrogen-oxygen, molten carbonate, PEM, and hydrocarbon-oxygen fuel cells. Applications of fuel cells currently include buses and cars that run on hydrogen fuel cells. With further technological advancements, fuel cells could potentially be used more widely for clean energy in industries and to power electronic devices. However, fuel cells also have limitations like high costs and needing specific operating conditions.

1. SEMINAR
FUEL CELLS
Presented by:
Rahein Rizwan
B.Sc, 2ND semester
Roll no: 1324

2. CONTENTS
 Introduction
 Fuel cell system
 Common types of fuel cells
 Present applications & future use
 Conclusion

3. INTRODUCTION
 FUEL CELLS: devices that convert energy of a fuel into
electrical energy without the use of a heat engine.
 BATTERY: general electrochemical device that we are
familiar with.
has all of its chemicals stored inside
converts those chemicals into electricity.
 eventually "goes dead“- we either throw it away or recharge it.
 Block diagram:

4. FUELCELLSYSTEM
1
• The fuel(direct or reformed H2 ) undergoes oxidation at anode that
generates protons and electrons .
2 • The electrons flow through the external circuit to the cathode
3 • At the cathode, the oxidant(O2) gets reduced.
4 • The electrons produce electricity while passing through the external circuit.

5. Typesoffuelcells:
HYDROGEN – OXYGEN FUEL CELLS
MOLTEN CARBONATE FUEL CELLS
PEM FUEL CELLS
HYDROCARBON - OXYGEN FUEL CELLS

6. Hydrogen–oxygenfuelcells
 Porous graphite electrodes
 Compressed with catalyst e . g . Pt , Ag
etc
 Electrodes-in contact with KOH/ NaOH
 O2 and H2 are continuously fed into
the cell.
Consists of-
Anodic reaction: H2  2H+ + 2e-
2H+ + 2OH-
=>2H2O
Cathodic reaction: 2H+ + ½O2 + 2e-  H2O
Net reaction: H2 + ½o2 H2o
Fig.A H2-O2 fuel cell

7.  Electrolyte: molten carbonate salt mixture
 Evolved in the 1960's aimed at producing a fuel
cell which would operated directly on coal .
 Operation on coal-derived fuel gases or natural
gas is viable.
Molten Carbonate Fuel Cells
- MCFC

8. Molten Carbonate Salt used as Electrolyte in MCFC
 The composition of the electrolyte (molten carbonate
salt mixture) varies, but usually consists of lithium
carbonate and potassium carbonate.
 At the operating temperature of about 650oC (1200oF),
the salt mixture is liquid and a good ionic conductor.
 The electrolyte is suspended in a porous, insulating
and chemically inert ceramic (LiAlO3) matrix.
Molten Carbonate Fuel Cells
- MCFC

9. The anode process involves a reaction
between hydrogen and carbonate ions
(CO3
2-) from the electrolyte.
The reaction produces water and carbon
dioxide (CO2) while releasing electrons to
the anode.
The cathode process combines oxygen and
CO2 from the oxidant stream with
electrons from the cathode to produce
carbonate ions which enter the electrolyte.
The need for CO2 in the oxidant stream
requires a system for collecting CO2 from
the anode exhaust and mixing it with the
cathode feed stream.
I
REACTIONS IN MCFC:
Fig. A molten carbonate fuel cell

10. PEMFC: Proton Exchange
Membrane Fuel Cell
Fig.A PEM fuel cell

11. Four Basic Elements in a
PEMFC
The electrolyte is the proton exchange
membrane.
specially treated material looks
something like ordinary kitchen plastic
wrap,
only conducts positively charged ions.
The membrane blocks electrons.
The catalyst is a special material that
facilitates the reaction of oxygen and
hydrogen.
It is usually platinum powder coated
onto carbon paper.
Rough and porous so that the maximum
surface area of the platinum can be
exposed to the hydrogen or oxygen.
The platinum-coated side of the catalyst
faces the PEM
Anode:
It conducts the electrons that are freed
from the hydrogen molecules
so that they can be used in an external
circuit.
It has channels etched into it that disperse
the hydrogen gas equally over the surface of
the catalyst.
Cathode:
has channels etched into it that distribute
the oxygen to the surface of the catalyst.
It also conducts the electrons back from
the external circuit to the catalyst,
where they can recombine with the
hydrogen ions and oxygen to form water.

12. Meanwhile, on the cathode side of the fuel cell,
oxygen gas (O2) is being forced through the
catalyst, where it forms two oxygen atoms.
Each of these atoms has a strong negative
charge.
This negative charge attracts the two H+ ions
through the membrane, where they combine
with an oxygen atom and two of the electrons
from the external circuit to form a water
molecule (H2O).
This reaction in a single fuel cell produces only
about 0.7 volts.
To get this voltage up to a reasonable level,
many separate fuel cells must be combined to
form a fuel-cell stack.

13. Hydrocarbon–oxygenfuelcells
 Based on the combustion of hydrocarbons such as
CH4,C2H5,C3H8etc.
 Pt-used as catalyst.
 Following reactions takes place

14. PRESENT APPLICATION & FUTURE OF FUEL CELLS:
• Some automobile companies have recently introduced buses, cars
which run on hydrogen fuel cells.
• Could be used in industries,etc as a clean fuel
• Could be used to power electronic devices

15. CONCLUSION
 Efficient and Clean(if H2 as fuel)
 Expensive and requires specific conditions
(temperature,humidity and pressure)
 With more tech advancements,could be used in
mass production for various applications.
 Not an instant fix for energy crisis but can act as
a major component.
 Hydrogen is difficult to store and distribute.

16. Thank you