---
title: "What is an Alkaline battery made of?"
description: "Zinc powder and manganese dioxide either side of a potassium hydroxide paste, in a steel can. Every component, the material it uses, and the constraint that made tha"
url: https://atoneplace.net/made-of/alkaline-battery/
site: "At One Place"
---

# What is an Alkaline battery made of?

**What is an Alkaline battery made of?: Zinc powder and manganese dioxide either side of a potassium hydroxide paste, in a steel can.**

The white crust on a leaked battery is potassium hydroxide that has reacted with carbon dioxide in the air, and it is caustic — it damages skin and eyes and eats the springs in the device. Leaking happens because a fully discharged cell generates hydrogen gas, pressure rises and the seal gives way, which is why devices should not be left with dead cells in them. Alkaline cells lost their mercury content in the 1990s, so in most jurisdictions they can go in the bin, but recycling recovers the zinc, manganese and steel. Rechargeable NiMH cells sit at 1.2 V rather than 1.5 V, which is why some devices report them as flat almost immediately.

## Component by component

*Every material is a choice, and the third column is the constraint that drove it.*

| Part | Material | Why that material |
| --- | --- | --- |
| anode | powdered zinc in a gel | Powder gives an enormous surface area, so the cell can deliver useful current from a metal that would otherwise react too slowly. |
| cathode | manganese dioxide mixed with graphite | Manganese dioxide is cheap and abundant; the graphite is there because MnO2 itself barely conducts. |
| electrolyte | potassium hydroxide solution — the alkali the battery is named for | An alkaline electrolyte lets the cell hold voltage under load far better than the old zinc-carbon acid design. |
| separator | a nonwoven fabric layer | It keeps the two pastes apart while letting ions cross; if it fails the cell shorts internally and heats up. |
| can and seal | nickel-plated steel can with a nylon seal and a vent | The steel can is the cathode current collector; the vent lets hydrogen escape rather than bursting, which is why cells leak instead. |

## Other electronics objects

- [Smartphone screen](https://atoneplace.net/made-of/smartphone-screen/) — Chemically strengthened aluminosilicate glass over a touch layer and an OLED or LCD panel, with an oil-shedding coating on top.
- [Solar panel](https://atoneplace.net/made-of/solar-panel/) — Doped silicon wafers with silver contacts, sealed between low-iron glass and a plastic backsheet in an aluminium frame.
- [LED bulb](https://atoneplace.net/made-of/led-bulb/) — Blue LED chips under a yellow phosphor, plus a driver circuit and a heat sink — and it is the driver that dies.
- [Touchscreen](https://atoneplace.net/made-of/touchscreen/) — A grid of transparent electrodes measuring the tiny capacitance your finger adds — which is why gloves fail.
- [Computer keyboard](https://atoneplace.net/made-of/keyboard/) — ABS or PBT keycaps over either a silicone rubber dome on printed film, or individual mechanical switches.
- [Headphones](https://atoneplace.net/made-of/headphone/) — A neodymium magnet, a coil of copper wire and a thin plastic diaphragm — a loudspeaker shrunk to fit an ear.
- [Loudspeaker](https://atoneplace.net/made-of/speaker/) — A paper or plastic cone hung on a rubber surround, driven by a coil in a magnet gap.
- [Computer mouse](https://atoneplace.net/made-of/computer-mouse/) — An ABS shell around a tiny camera taking thousands of pictures a second, plus two clicky microswitches and PTFE feet.

## Common questions

### What is an Alkaline battery made of?

Zinc powder and manganese dioxide either side of a potassium hydroxide paste, in a steel can.

### What is the anode of an Alkaline battery made of?

Powdered zinc in a gel. Powder gives an enormous surface area, so the cell can deliver useful current from a metal that would otherwise react too slowly.

### What is the cathode of an Alkaline battery made of?

Manganese dioxide mixed with graphite. Manganese dioxide is cheap and abundant; the graphite is there because MnO2 itself barely conducts.

## Related pages

- [Smartphone screen](https://atoneplace.net/made-of/smartphone-screen/)
- [Solar panel](https://atoneplace.net/made-of/solar-panel/)
- [LED bulb](https://atoneplace.net/made-of/led-bulb/)
- [Touchscreen](https://atoneplace.net/made-of/touchscreen/)
- [Computer keyboard](https://atoneplace.net/made-of/keyboard/)
- [Headphones](https://atoneplace.net/made-of/headphone/)
- [Loudspeaker](https://atoneplace.net/made-of/speaker/)
- [Computer mouse](https://atoneplace.net/made-of/computer-mouse/)
- [Pencil](https://atoneplace.net/made-of/pencil/)
- [Tennis ball](https://atoneplace.net/made-of/tennis-ball/)
- [Banknote](https://atoneplace.net/made-of/banknote/)
- [Golf ball](https://atoneplace.net/made-of/golf-ball/)
- [Paper](https://atoneplace.net/made-of/paper/)
- [Glass](https://atoneplace.net/made-of/glass/)

## Sources

- Typical range compiled from manufacturer specifications — At One Place (/about/)