1.5V AA and AAA Lithium Batteries
1.5V lithium batteries are not as common as 3.0+ volts lithium batteries, but their popularity is increasing over time. The main advantages of 1.5V lithium batteries over zinc-carbon and alkaline batteries are improved capacity especially for high-discharge applications, extra-long shelf life (20+ years) due to the very low self-discharge rate, wider operating temperature range, somewhat lower weight, etc.
Lithium 1.5V batteries are mostly based on the LiFeS2 (Lithium Iron Disulfide) chemistry, although other versions are also possible, for example, Li-CuFeS2 (Lithium Copper Iron Disulfide).
Rechargeable Lithium-ion (3.7V) and Lithium Iron Phosphate (3.2V) batteries are offered with built-in DC-DC converters with a very constant 1.5V output voltage, making them directly compatible with Zinc-Carbon and Alkaline 1.5V batteries, but also featuring 1000+ charging/discharging cycles.
Published: September 18, 2021.
AA and AAA Battery Chemistries
Lithium Iron Disulfide 1.5V batteries feature a nominal voltage of 1.5 volts and open-circuit voltage of ~1.8V, which drops quickly down to 1.5 volts as soon as the load is applied, making Lithium Iron Disulfide directly compatible with Zinc-Carbon and Alkaline batteries.
Lithium Iron Disulfide chemistry is mostly used in AA and AAA batteries.
Lithium non-rechargeable 1.5V AA batteries feature physical dimensions of (D x H) 14.5 x 50.5 mm, a nominal voltage of 1.5 volts, and nominal capacity in the 2700-3300 mAh range. Also, their shelf life is up to or even longer than 20 years, making them suitable for standby applications, medical instruments, security applications, and similar.
Rechargeable AA Lithium-ion (3.7V) and Lithium Iron Phosphate (3.2V) batteries feature the built-in DC-DC converters ensuring a very constant 1.5V output voltage, making them directly compatible with Zinc-Carbon and Alkaline AA 1.5V batteries. But, such batteries also featuring 1000+ charging/discharging cycles - in order to prolong their lifetime, it is recommended to recharge them every 3-6 months, when the batteries are not in use.
The following comparison chart lists some of the most popular AA/14500 battery 1.5V chemistries with their most important features and specifications:
| Chemistry | Common Name | Rechargeable | Typical Capacity (mAh) | Voltage (V) |
| Zinc Carbon | R6, 15D | No | 600 - 1600 | 1.5 |
| Alkaline | LR6, 15A | No (Mostly No) | 1800 - 2700 | 1.5 |
| Li-FeS2 | FR6, 15LF | No | 2700 - 3300 | 1.5 (1.8 max) |
| Li-ion | 14500 | Yes | 600 - 2000+ | 3.6 - 3.7 |
| LiFePO4 | IFR14500 | Yes | 500-750 | 3.2 |
| Li-SOCl2 | (14505) | No | 2400-2700 | 3.5-3.6 |
| Li-MnO2 | CR AA | No | ~2000 | 3.0 |
| Lithium | - | Yes | 1000-2000+ | 1.5 |
| NiCd | KR6, 1.2K2 | Yes | 600 - 1200 | 1.2 |
| NiMH | HR6, 1.2H2 | Yes | 700 - 2800 | 1.2 |
| NiOOH | - | No | 2200 - 2700 | 1.5 (1.7 max) |
| NiZn | ZR6 | Yes | 1500 - 1800 | 1.6 - 1.65 |
Of course, there are other lithium (and non-lithium) chemistries present or being developed, but these are the most popular ones.
Lithium 1.5V AAA batteries feature physical dimensions of (D x H) 10.5 x 44.5 mm, a nominal voltage of 1.5 volts. Due to the smaller dimensions lithium 1.5V AAA batteries also feature smaller capacity, which is usually in the 1100-1300 mAh range.
Rechargeable AAA Lithium-ion (3.7V) and Lithium Iron Phosphate (3.2V) batteries feature the built-in DC-DC converters ensuring a very constant 1.5V output voltage, making them directly compatible with Zinc-Carbon and Alkaline AAA 1.5V batteries. But, such batteries also featuring 1000+ charging/discharging cycles - in order to prolong their filetime, it is recommended to recharge them every 3-6 months, when the batteries are not in use.
The following comparison chart lists some of the most popular AAA/10440 battery 1.5V chemistries with their most important features and specifications:
| Chemistry | Common Name | Rechargeable | Typical Capacity (mAh) | Voltage |
| Zinc Carbon | R03, 24D | No | 500-600 | 1.5 |
| Alkaline | LR03, 24A | Mostly No | 850-1200 | 1.5 |
| Li-FeS2 | FR03, 24LF | No | 1100-1300 | 1.5 (1.8 max) |
| Li-ion | 10440 | Yes | 350-600 | 3.6 - 3.7 |
| LiFePO4 | IFR10440, IFR10450 | Yes | 250-300 | 3.2 |
| Li-SOCl2 | (10450) | No | 600-800 | 3.6-3.7 |
| Lithium | - | Yes | 400-600 | 1.5 |
| NiCd | KR03, 24K | Yes | 300-500 | 1.2 |
| NiMH | HR03, 24H | Yes | 600-1300 | 1.2 |
| NiOOH | ZR03 | No | 1000-1200 | 1.5 (1.7 max) |
| NiZn | - | Yes | 500-700 | 1.6 - 1.65 |
Lithium Iron Disulfide is a relatively cheap technology, but it is still relatively new on the market.
However, if You are in a position to choose between a Lithium Iron Disulfide 1.5V battery from reputable brands and an Alkaline 1.5V battery from the same or similar brand, and the battery price difference is not of an issue, go for the Lithium Iron Disulfide battery type.