The Energizer Ultimate Lithium is an amazing product. If you need a battery that you don't want to replace often, this is the thing.

Energizer® Ultimate Lithium™ Batteries Nothing outlasts Energizer® Ultimate Lithium™ AA batteries. The Energizer® Ultimate Lithium™ batteries are not only the #1 longest-lasting AA batteries…they are complete with leak resistance and performance in extreme temperatures (-40ºF to 140ºF or -40ºC to 60ºC).

up to 20 years Energizer® Ultimate Lithium™ AA and AAA last up to 20 years in storage, while our 9V lasts up to 10 years in storage. Energizer Recharge® AA, AAA, C, D, and 9V last charged up to 12 months in storage, with a battery life of up to 5 years under normal conditions for AA and AAA batteries.

The chemical reaction begins when the battery becomes part of an external circuit through which the electrons flow between electrodes. The lithium atoms release electrons to become positive ions (Li+); the manganese atoms gain them, thereby going from Mn4+ to Mn3+.

Safe, Stable Chemistry One of the most important advantages LiFePO4 has over other battery types is safety. LiFePO4 is the safest lithium battery type. It's the safest of any type, actually. Overall, LifePO4 batteries have the safest lithium chemistry.

The true advantage of Energizer™ NiMH rechargeable batteries can be found in the cycle life (resuse after charging). AA, AAA up to 5 years usable life; C, D, 9V up to 3 years shelf life.

Lithium is the lightest, most active metal. When this powerful metal is paired with iron disulfide, this energy is available at a voltage suitable for 1.5 volt applications. Energizer® successfully produced the first commercially available “AA” size 1.5 volt lithium battery in 1989.

AA batteries The Energizer® Ultimate Lithium™ batteries are the #1 longest-lasting AA batteries – complete with leak resistance and performance in extreme temperatures (-40ºF to 140ºF or -40ºC to 60ºC).

A typical charge or use cycle for a lithium-ion battery is 8 hours of use, 1 hour to charge and another 8 hours of use. No cool down period is needed. This allows the battery to be used continuously throughout a 24-hour shift, with downtime occurring only during short periods of opportunity charging.

From the manufacturer

The anode and cathode store the lithium. The electrolyte carries positively charged lithium ions from the anode to the cathode and vice versa through the separator. The movement of the lithium ions creates free electrons in the anode which creates a charge at the positive current collector.

Lithium, an exceptionally light metal, gives lithium batteries the highest energy density of any battery cell. Thus, they can store more energy than alkaline batteries or any single-use battery of a comparable size. And they are superb performers in extreme temperatures, both hot and cold.