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Alkaline batteries are a type of power cell dependent upon the reaction between zinc and manganese dioxide (Zn/MnO₂).

Compared with original zinc-carbon batteries, while both produce approximately 1.5 volts per cell, alkaline batteries have a higher energy density and longer shelf-life.

Compared with silver-oxide batteries, which alkalines commonly compete against in button cells, they have lower energy density and shorter lifetimes.

The alkaline battery gets its name because it has an alkaline electrolyte of potassium hydroxide.

Contents 1 Chemistry 2 Capacity 3 Leaks 4 Disposal 5 See also 6 References 7 External links

In an alkaline battery, the anode (negative terminal) is made of zinc powder (allows more surface area for increased rate of reaction therefore increased electron flow) and the cathode (positive terminal) is composed of manganese dioxide. When describing standard "AAA", "AA", "C", "sub-C" and "D" type cells, the anode is the raised "button" end while the cathode is the flat end.

So far, they are comparable to zinc-carbon batteries, but the difference is that alkaline batteries use potassium hydroxide (KOH) as an electrolyte rather than ammonium chloride or zinc chloride.

The half-reactions are:^[1]

and

Unlike NiMH rechargeable batteries, alkaline batteries are normally not sold with a nominal capacity. Alkalines have a high internal resistance, and a high thermal coefficient of resistivity - the faster you drain an alkaline, the higher percentage of the load it dissipates as heat. Therefore, the capacity of an alkaline battery is strongly dependent on the load, even at moderate loads. A AA-sized alkaline battery might have an effective capacity of 3000 mAh at low power, but at a load of 1000 mA, which is common for digital cameras, the capacity could be as little as 700 mAh.^[2]

Over time, alkaline batteries are prone to leaking potassium hydroxide, a caustic agent that can cause respiratory, eye and skin irritation. This can be avoided by not mixing different battery types in the same device, replacing all of the batteries at the same time, storing in a dry place, and removing batteries from devices for storage.

Unlike other types of batteries, Alkaline batteries can be disposed of in the regular trash in most locations. ^[3], ^[4] The state of California, however, has made it illegal to throw alkaline batteries in the trash.

• Oxyride battery
• Rechargeable battery
• Rechargeable alkaline battery
• List of battery sizes

1. ^ Battery FAQ at www.powerstream.com
2. ^ Alkaline Drain Chart at greenbatteries.com
3. ^ Battery Recycling and Disposal Guide at ehso.com
4. ^ Household battery fact sheet at dec.ny.gov

• Big Green Box - Easy Battery Recycling & Disposal
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