Alkaline Batteries

• reaction between zinc metal and manganese dioxide
• higher energy density and longer shelf life yet provide the same voltage than zinc-carbon batteries

Chemistry

Zinc is oxidized:

• Zn → Zn²⁺ + 2e⁻
• Anode (negative electrode): Zinc (Zn)

Manganese dioxide is reduced:

• MnO₂ + H₂O + e⁻ → MnOOH + OH⁻
• Manganese dioxide (MnO₂) forms manganese oxyhydroxide
• Cathode (positive electrode):

Electrolyte: Potassium hydroxide (KOH), an alkaline solution

• KOH → K⁺ + OH⁻
• The K0H splits in water, and the potassium remains in solution
• OH- is also generated and restalked via the MnO₂ reaction

| Layer                 | Material/Description              |
|-----------------------|-----------------------------------|
| Positive Terminal     |                                   |
| Manganese Dioxide     | Cathode - gain electrons          |
| Porous Separator      | Allows ion flow, no direct contact|
| Electrolyte           | Potassium hydroxide (KOH)         |
| Zinc Anode            | Anode - lose electrons            |
| Negative Terminal     |                                   |