A lithium battery is any battery that uses lithium as part of its chemistry, whether it contains pure metallic lithium or lithium-based compounds. This covers a surprisingly wide range of everyday items: the rechargeable battery in your phone, the coin cell in your car key fob, the power pack in your laptop, and the battery driving an electric vehicle. If it has lithium in its electrodes or electrolyte, it counts.
The distinction matters most when you’re shipping packages, boarding a plane, or disposing of old batteries. Regulations treat lithium batteries differently from standard alkaline cells because lithium stores more energy and carries a higher fire risk if damaged. Knowing what counts helps you stay compliant and handle these batteries safely.
The Two Main Categories
All lithium batteries fall into one of two groups: lithium metal and lithium-ion. The difference comes down to whether you can recharge them.
Lithium metal batteries are single-use. They contain pure metallic lithium as one electrode, which reacts chemically to produce electricity. Once that reaction is spent, the battery is dead. These batteries have an exceptionally long shelf life of 10 to 12 years, which is why they’re used in smoke detectors, watches, medical devices, and backup memory chips. The most familiar examples are coin cells and button cells with designations like CR2032 or CR123A.
Lithium-ion batteries are rechargeable. Instead of pure lithium metal, they use a graphite electrode on one side and a lithium-based compound on the other. Lithium ions shuttle back and forth between these two electrodes as the battery charges and discharges, allowing over 1,000 recharge cycles in many designs. The tradeoff is a shorter shelf life of two to three years. These are the batteries in smartphones, laptops, tablets, power tools, e-bikes, electric vehicles, portable chargers (power banks), wireless earbuds, and home energy storage systems.
How to Identify a Lithium Battery
Voltage is the quickest clue. A standard alkaline battery (AA, AAA, C, D) runs at 1.5 volts per cell. Lithium-ion cells typically have a nominal voltage of 3.6 or 3.7 volts, and some newer chemistries reach 3.8 to 3.85 volts. Lithium iron phosphate cells run at 3.2 to 3.3 volts. Lithium metal coin cells produce 3.0 volts. If a single cell puts out more than 1.5 volts, there’s a good chance it’s lithium-based.
Label codes also help. The IEC prefix “CR” on a coin or cylindrical battery means lithium manganese dioxide chemistry. “BR” indicates a lithium carbon monofluoride cell. Both are lithium metal (non-rechargeable). Rechargeable lithium-ion packs are usually labeled “Li-ion” or “LiPo” (lithium polymer, a variation that uses a gel-like electrolyte instead of liquid). Most will also print the voltage and capacity in milliamp-hours (mAh) or watt-hours (Wh) on the casing.
Common Lithium-Ion Chemistry Types
Not all lithium-ion batteries are identical inside. Different cathode materials give them different strengths, but they all count as lithium batteries under regulations and safety guidelines.
- NMC (nickel manganese cobalt): Widely used in electric vehicles and power tools. Offers a good balance of energy density, power output, and lifespan.
- LFP (lithium iron phosphate): Common in home energy storage, some electric vehicles, and commercial backup systems. More thermally stable and longer-lasting, but stores slightly less energy per pound.
- LCO (lithium cobalt oxide): The original rechargeable lithium-ion chemistry, commercialized by Sony in 1991. Still used in smartphones and laptops where compact size matters most.
- LiPo (lithium polymer): Uses the same basic chemistry as other lithium-ion cells but with a flexible pouch design and polymer electrolyte. Found in drones, slim laptops, and wearable devices.
All of these are lithium-ion batteries regardless of their specific internal compounds.
Everyday Devices That Contain Lithium Batteries
The list is longer than most people expect. Any rechargeable portable device made in the last 15 years almost certainly uses a lithium-ion or lithium polymer battery. This includes smartphones, tablets, laptops, smartwatches, wireless headphones, Bluetooth speakers, handheld gaming consoles, e-readers, digital cameras, vape devices, electric toothbrushes, robot vacuums, and portable jump starters.
Lithium metal (non-rechargeable) batteries show up in places where long shelf life and reliability matter: hearing aids, car key fobs, garage door remotes, calculators, thermometers, glucose monitors, smoke alarms, and BIOS backup batteries on computer motherboards. If a small device uses a coin cell or a cylindrical battery labeled “CR” or “BR,” that’s lithium metal.
Larger applications also count. Electric vehicle battery packs, home solar storage units like the Tesla Powerwall, and grid-scale energy storage installations all use lithium-ion chemistry. So do electric scooters, e-bikes, hoverboards, and electric skateboards.
Why It Matters for Air Travel
Airlines and the TSA regulate lithium batteries separately from other battery types because of their higher energy density and fire risk. The rules differ based on battery type and size.
Lithium-ion batteries must not exceed 100 watt-hours each. Lithium metal batteries are limited to 2 grams of lithium content per battery. Batteries within those limits can go in carry-on or checked bags when installed in a device, but spare (uninstalled) lithium batteries of either type must go in carry-on luggage only. This includes power banks and phone battery cases, since those are effectively spare batteries.
With airline approval, you can bring up to two larger spare lithium-ion batteries rated between 101 and 160 watt-hours, or lithium metal batteries containing 2 to 8 grams of lithium. Anything above those thresholds is generally prohibited on passenger aircraft.
How to Calculate Watt-Hours
Most consumer batteries print their capacity in milliamp-hours (mAh) rather than watt-hours, so you may need to do the conversion yourself to check against the 100 Wh airline limit. The formula is straightforward: multiply the milliamp-hour rating by the voltage, then divide by 1,000.
For example, a typical portable charger rated at 20,000 mAh and 3.7 volts works out to 74 Wh (20,000 × 3.7 ÷ 1,000), which falls under the limit. A laptop battery rated at 5,000 mAh at 14.8 volts comes to 74 Wh as well. Most smartphone batteries land between 10 and 20 Wh, well within the threshold. You’d need a very large battery pack to exceed 100 Wh, but it’s worth checking for high-capacity power banks, professional camera equipment, and portable power stations.
Lithium vs. Non-Lithium Batteries
Standard alkaline batteries (AA, AAA, 9-volt) do not contain lithium and are not subject to lithium battery regulations. The same goes for nickel-metal hydride (NiMH) rechargeables, the older nickel-cadmium (NiCd) type, and lead-acid batteries like car starter batteries. These use entirely different chemistries and carry different risk profiles.
There is one point of confusion: some companies sell lithium iron disulfide AA and AAA batteries (sold under brand names like Energizer Ultimate Lithium). These are single-use lithium metal batteries shaped to fit standard AA/AAA devices, and they do count as lithium batteries despite looking identical to alkaline cells. They run at 1.5 volts like alkaline batteries but contain lithium metal inside. The packaging will say “lithium” on it.