AAA lithium Batteries are a direct, non-rechargeable replacement for alkaline batteries of the same size. These batteries are extremely lightweight and provide better performance under load as well as a much longer shelf life than alkaline AAAs.
This case size is identical to the alkaline equivalent, measuring 10.5mm in diameter × 44.5mm long. It is commonly known as a “microlight” format and may also be called MN2400 or MX2400. This size is widely used in micro torches, wireless remote controls, clocks, calculators, toys, games and other consumer electronics. Output potential is 1.5V and the most typical configuration is a pair connected in series to provide 3V, although single-cell supplies are also common.
The considerable weight reduction over alkaline, as well as the increased energy capacity is due to the use of a lithium foil anode with a propylene carbonate electrolyte and, typically, a iron disulfide cathode. This construct provides up to 2.5 times the energy capacity of an alkaline cell and greatly reduces self-discharge potential, providing a shelf life of as long as 10 years. The common name for the technology is Li/Fe (lithium/iron).
For applications that use AAA batteries, these cells offer a disposable alternative to alkaline that will last much longer under load and can be discarded with less risk to the environment than many other types. The light weight makes these a good choice for fliers or backpackers and because of their long shelf life, several sets of replacements can be kept on hand.