니켈-카드뮴 전지. Ni-Cd battery

니켈-카드뮴 전지. Ni-Cd battery

 

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Cd + 2NiOOH + 2H2O → 2Ni(OH)2 + Cd(OH)2

 

 

This battery uses nickel oxide in its positive electrode (cathode),

a cadmium compound in its negative electrode (anode),

and potassium hydroxide solution as its electrolyte.

 

 

Nickel-Cadmium battery is rechargeable.

 

In a fully discharged Ni-Cd battery, the cathode contains nickel hydroxide [Ni(OH)2] and cadmium hydroxide [Cd(OH)2] in the anode.

 

When the battery is charged, the chemical composition of the cathode is transformed and the nickel hydroxide changes to nickel oxyhydroxide [NiOOH].

In the anode, cadmium hydroxide is transformed to cadmium.

As the battery is discharged, the process is reversed, as shown in the following formula.

2NiOOH + Cd + 2H2O → 2Ni(OH)2 + Cd(OH)2

 

 

> anode: Cd + 2OH^- → Cd(OH)2 + 2e^-

> cathode: 2NiO(OH) + 2H2O + 2e^- → 2Ni(OH)2 + 2OH^-

> overall: Cd + 2NiO(OH) + 2H2O → 2Ni(OH)2 + Cd(OH)2