Zinc and manganese dioxide cell with potassium hydroxide electrolyte providing long life.
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The alkaline battery uses a zinc powder anode, a manganese dioxide cathode and potassium hydroxide as the electrolyte. The powdered zinc presents a large surface area, and the alkaline medium allows a more complete reaction, giving higher capacity and longer shelf life than the zinc-carbon cell. It still delivers about 1.5 V and is not rechargeable in normal use. The electrolyte is less prone to leakage and gas build-up than the acidic paste of a dry cell. Alkaline batteries are the standard choice for devices with moderate or high drain.
Key ideas: Zn powder anode and MnO2 cathode in KOH electrolyte. Anode: Zn + 2OH- giving ZnO + H2O + 2e-. Cathode: 2MnO2 + H2O + 2e- giving Mn2O3 + 2OH-. About 1.5 V, longer shelf life and greater capacity than zinc-carbon, and better at high current because KOH is highly conductive.
Common mistakes and connections: Mistake: thinking OH- is consumed overall; it is regenerated, so electrolyte concentration stays roughly constant. Most are not rechargeable, and attempting to charge them can cause leaks or rupture. The steel case is the current collector, not an electrode reactant. Compare with Leclanche cell for chemistry differences.
The alkaline cell uses powdered zinc in KOH for more surface area and a more complete reaction, giving 1.5 V with a longer life than zinc-carbon. The interactive lesson shows this as a live animation or chart.
An alkaline AA cell provides about 1.5 V and can last several times longer than a zinc-carbon cell in a radio.
Zinc and manganese dioxide cell with potassium hydroxide electrolyte providing long life.
Alkaline Battery is a intermediate topic in Acids, Bases & Electrochemistry. It builds on the vocabulary of beginner topics in this area.
Study these earlier topics in Acids, Bases & Electrochemistry first: Hall-Heroult Process, Chlor-Alkali Process, Dry Cell.
The next topics in Acids, Bases & Electrochemistry are Lead-Acid Battery and Lithium-Ion Battery.
Yes. The interactive lesson includes a self-check question on Alkaline Battery, and the Acids, Bases & Electrochemistry quiz draws on every topic in this area.
Alkaline Battery is topic 69 of 105 in Acids, Bases & Electrochemistry.