Common Voltage and Chemistry for AA Sized Batteries
Primary AA batteries
AA Alkaline - typically 1.5 volt, non-rechargeable
Lithium - 1.5 to 3.6 volt, non-rechargeable
AA Nickel Oxyhydroxide - typically 1.7 volt, non-rechargeable
Secondary AA batteries
AA NiCD - typically 1.2 volt, rechargeable
AA NiMH - typically 1.2 volt, rechargeable
AA Alkaline vs. AA Lithium
You may have noticed by now that the AA batteries we carry are pretty similar in capacity. Whether these batteries are disposable or rechargeable, alkaline or lithium, most of the AA batteries hold 2300 mAh to 3000 mAh of reserve power. As an example, Energizer E91 (alkaline) vs. L91 (lithium) are very similar in capacity, 2850 mAh vs. 3000 mAh respectively. How then, does Energizer claim that L91 lasts 8 times longer than E91? The secret lies in the chemistry and the construction of the battery.
AA Alkaline batteries generate electricity from a reaction between zinc electrodes and manganese oxide paste, where the application would be optimal for low draining devices such as clocks, calculators and remote controllers due to the slow reaction time. When the power is drawn out quickly such as when taking a picture with flash, the battery cannot react fully throughout the battery and coats unused zinc electrodes with depleted reactants. As a consequence, the alkaline battery may lose its total capacity by half, or by as much as 2/3, lasting shorter than its intended cycle life.
Lithium batteries are constructed differently and have a much larger area for reaction, allowing as much power to be drawn out of the battery as possible. In other words, Energizer's claim of L91 AA batteries lasting up to 8 times longer is not because of bigger capacity, but efficiency of drain.