H2-O2 CELLA

1. FUEL CELLS
BY
CHILUKURI PAVAN CHOWDARY
17321

2. HISTORY OF FUEL CELLS
 The first fuel cells were INVENTED by Sir WILLIAm GROVe in 1838.
 The invention of the hydrogen–oxygen fuel cell for
COMMERCIAL USE BY FRANCIs THOmAs BACON in 1932.

3.  WHAT IS A FUEL CELL ?
 A Fuel Cell is an electrochemical device that combines hydrogen and
oxygen to produce electricity, with water and heat as its by-product.
 It is an energy conversion device or electricity generator.
 It is an example for a primary cell.
 This is capable of supplying current as long as it is provided with the supply of
reactants.
 GENERAL EQUATION :
FUEL + OXYGEN →OXIDATION PRODUCTS + ELECTRICITY
(OXIDANT)

4. FUEL CELL

5. HOW DOES A FUEL CELL WORK
 It operates similarly to a battery, but it does not run down nor does it require
recharging
 As long as fuel is supplied, a Fuel Cell will produce both energy and HEAT
 A Fuel Cell consists of two catalyst coated electrodes surrounding an
electrolyte
 One electrode is an anode and the other is a cathode
 The process begins when Hydrogen molecules enter the anode
 The catalyst coating separates hydrogen’s negatively charged electrons
from the positively charged protons.

6. HOW DOES A FUEL
CELL WORK
 The electrolyte allows the protons to pass through to the cathode, but not
the electrons
 Instead the electrons are directed through an external circuit which
creates electrical current
 While the electrons pass through the external circuit, oxygen molecules
pass through the cathode
 There the oxygen and the protons combine with the electrons after they
have passed through the external circuit

7. HOW DOES A FUEL CELL WORK ???
 When the oxygen and the protons
combine with the electrons it
produces water and heat.
Picture of fuel cell

8. mOsT ImPORTANT CHARACTeRIsTICs
 High efficiency
 Low emission levels
 Low noise levels
 Fuel cells are free from vibration, heat transfer and
thermal pollution

9. EXAMPLES OF FUEL CELLS
 HYDROGEN-OXYGEN CELLS
Types of H2-O2 Fuel Cell
 Alkaline fuel cells (AFC)
 Phosphoric acid fuel cells(PAFC)
 Molten carbonate fuel cells(MCFC)
 Solid oxide fuel cells(SOFC)
 Proton exchange membrane fuel cells (PEMFC)

10. HYDROEN-OXYGEN FUEL CELL(H2-O2)
 A common type of fuel cell based on the combustion of hydrogen gas.
Equation : 2H2 + O2 2H2O
(g) (g) (l)

12.  consists two electrodes
 made up of graphite
 catalyst platinum or metal oxide
 placed in aqueous solution (KOH or NAOH)
 H2 Gas evolves in anode
 O2 Gas evolve in cathod
REACTION
 AT Anode
H2 + 2OH− → 2H2O + 2e−
(g) (aq) (L)
 AT CATHOD
O2(g) + 2H2O + 4e− → 4OH
(g) (l)
2H2 + O2 → 2H2O
(g) (g) (L)

13.  THE Standard EMF Of H2 – O2 CELLS
E° = E°(cathode) - E°(anode)

14. USES OF H2 – O2 CELLS
• used in space craft because of their high
efficiency, lightness
• used in submarines or other military vehicles
• used as the primary source of electrical energy
on the Apollo moon flights. Approximately 200
kg of fuel is sufficient for 11 days in space

15. ADVANTAGES OF FUEL CELLS
 The energy conversion (chemical into
electrical) is very high by fuel cells (75-82.8%).
 H2-O2 fuel cell produces H2O, which is used as
drinking purpose by astronauts
 Noise and thermal pollution are low.
 Such type of cells never becomes dead,
because of continuous supply of fuel

16. ADVANTAGES OF FUEL
CELLS
Modular and other parts of fuel cells
are exchangeable
Fuels cells having low maintenance
cost
Fuels cells saves fossil fuels.

17. Disadvantages of Fuel Cells
 High initial cost.
 Large weight and volume of gas-fuel storage
system.
 High cost of pure hydrogen.
Life-times of such type of cells are not
accurately known.