Lithium isn't rechargable. (Lithium AA cells are very long-life but very expensive. One-time use. Lithium-ion are rechargable, but are 3.7 volts and completely violate the AA spec)
NiMH is the chemistry for rechargable AA / AAA cells, since its 1.35V and "close enough" to the old 1.5V standard alkaline.
> Older rechargeable AA and AAA batteries were terribly short lived and so mostly useless but I assume Lithium ones are much better?
"Older", circa 00s NiMH chemistries had more energy storage (!!!). The issue was that circa 00s cells had a "self-discharge" problem, meaning they ran out of energy in just a few months (like 1 to 3 months).
Panasonic solved the problem with "Low Self Discharge" cells, aka "Eneloop", which started to come out in the late 00s. This chemistry had much less capacity, but took over a year before the energy went bad.
Its still NiMH chemistry, but just tweaked to focus on the self-discharge problem rather than energy-storage numbers / benchmarks.
With Eneloop taking the market by storm (especially popular with XBox users, which used AA rechargables), other companies also came out with LSD chemistries. These days, almost everything you'll find is of the LSD-type.
You can get lithium ion rechargable AA batteries these days. They have a built in regulator to drop the voltage to 1.5V. Some of them even have micro usb ports on the side for charging.
Lithium isn't rechargable. (Lithium AA cells are very long-life but very expensive. One-time use. Lithium-ion are rechargable, but are 3.7 volts and completely violate the AA spec)
NiMH is the chemistry for rechargable AA / AAA cells, since its 1.35V and "close enough" to the old 1.5V standard alkaline.
> Older rechargeable AA and AAA batteries were terribly short lived and so mostly useless but I assume Lithium ones are much better?
"Older", circa 00s NiMH chemistries had more energy storage (!!!). The issue was that circa 00s cells had a "self-discharge" problem, meaning they ran out of energy in just a few months (like 1 to 3 months).
Panasonic solved the problem with "Low Self Discharge" cells, aka "Eneloop", which started to come out in the late 00s. This chemistry had much less capacity, but took over a year before the energy went bad.
Its still NiMH chemistry, but just tweaked to focus on the self-discharge problem rather than energy-storage numbers / benchmarks.
With Eneloop taking the market by storm (especially popular with XBox users, which used AA rechargables), other companies also came out with LSD chemistries. These days, almost everything you'll find is of the LSD-type.