Fuel cell is a galvanic cell in which chemical energy of fuel and oxidant (O2) system is converted in to electrical energy.

1. Fuel Cell
BY
CH. SAI SRI RAMA CHANDRA
MURTHY

2. Fuel cell:
Fuel cell is a galvanic cell in which chemical energy of fuel and
oxidant (O2) system is converted in to electrical energy.
Fuel + O2 Energy product
Eg: 1. Hydrogen oxygen fuel cell
H2 - O2 fuel cell
2. Methyl alcohol – Oxygen fuel cell
CH3OH – O2 fuel cell

3. Hydrogen–Oxygen cell:
Construction
1. It consists of two electrodes.
2. It is made up of porous graphite material coated with Platinum.
3. H2 is bubbled through anode O2 is bubbled through Cathode.

4. Anode: Inert porous graphite material coated with platinum.
Cathode: Inert porous graphite material coated with platinum.
Electrolyte: Potassium Hydroxide Solution (KOH)
Hydrogen gas, Oxygen gas are passed through anode and cathode.
At anode: Oxidation reaction takes place
2H2(g) + 4OH¯(aq) 4H2O(l) + 4e
At cathode: Reduction reaction takes place
O2(g) + 2H2O + 4e 4OH¯(aq)
Cell reaction: 2H2(g) +O2(g) 2H2O(l)

5. Anode: 2H2(g) + 4OH¯(aq) 4H2O(l) + 4e
Cathode: O2(g) + 2H2O + 4e 4OH¯(aq)
Cell: 2H2(g) +O2(g) 2H2O(l)
Applications:
1. They are used as auxillary energy source in space vehicle, submarines or
other military vehicles.
2. Because of light weight these fuel cells are preferred for space and
product H2O is a valuable fresh water sources for astronauts.

6. Advantages of Fuel Cells:
1. The following are the advantages of fuel cells:
2. The energy conversion is very high (75-82%).
3. The product H2O is a drinking water sources for astronauts.
4. Noise and thermal pollution are low.
5. The maintenance cost is low these for these fuels.
Limitations:
1. Their initial cost is high.
2. The distribution of hydrogen is not proper.

7. Methyl Alcohol – Oxygen Alkaline Fuel Cell
In this fuel cell, CH3OH is used as a fuel and O2 as oxidant generate
electrical energy.
They methyl alcohol-oxygen fuel cell has two electrode. The anode
consists of porous nickel electrode impregnated with Pt/Pd catalyst. Porous
nickel electrode coated with silver catalyst constitute a cathode of the cell.
The electrolytes, KOH, is taken in between the two electrodes. CH3OH and
O2 are sent continuously into their respective electrodes and the electrical
energy is produced with the continuous replenishment of the fuel, CH3OH at
the anode

9. At anode
CH3OH + 6OH¯ CO2 + 5H2O + 6e¯
At cathode
3/2 O2 + 3H2O + 6e¯ 6OH¯
Over all reactions
CH3OH + 3/2 O2 CO2 + 2H2O
Applications:
The major application of methyl alcohol-oxygen fuel cell is a fuel cell motor
vehicle like NECAR–5 in Japan, USA etc.

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