1. Applications of Electrochemical Cells: (Batteries)
The Dry Cell
Carbon (Cathode) e-
Paste of MnO2 , NH4Cl
Zinc (Anode)
Anode:
Zn  Zn e-
Cathode:
2MnO NH e-  2MnO(OH) + 2NH3
Ecell = 1.5 V
Poor diffusion of products.
The alkaline battery is similar, but includes a salt bridge of KOH and more reactants.

2. Silver Oxide Battery KOH e- Anode: Zn  Zn2+ + 2e- Cathode:
Ag2O
KOH e- Zn
Anode:
Zn  Zn e-
Cathode:
Ag2O + 2e-  2Ag + OH-
Used for watches, cameras, hearing aids…

3. Lead Storage Battery e- fill cap Pb PbO2 Anode:
H2SO4
Anode:
Pb + SO42-  PbSO e-
Cathode:
PbO H+ + SO e-  PbSO H2O
Ecell = 2.0 V
Reactions are reversed by applying an external voltage.
6 are connected in series = 12 V

4. Fuel Cells e- H2 O2 (air) Porous carbon Anode: H2 + 2OH-  2H2O + 2e-
KOH
Anode:
H OH-  2H2O + 2e-
Cathode:
O H2O + 4e-  4OH-
Overall:
2H2 + O2  2H2O
Produces electricity and water.