Lithium batteries are so called because the metal they originally used as plates is lithium based as apposed to, for example, lead in lead acid batteries. For disposable lithium batteries this is still true and hence they are known as lithium metal batteries. In the rechargeable version these plates have actually been replaced over time with non-lithium metals but the chemical process still relies on lithium ions and hence they are referred to as lithium-ion batteries.
Before their invention nickel based batteries served the market for rechargeable units while alkaline were most popular for those needing a disposable option.
Lithium offers numerous advantages:
- Higher specific energy – better Watt hours per kilogram (Wh/kg) ratings.
- Much higher cell voltage.
- Stable voltage during discharge.
- Better shelf life.
- Lower self-discharge (versus Nickel).
- Flexibility in shapes that can be manufactured.
- Literal flexibility with cells that can bend.
However lithium still has some limitations
- Safety issues make shipping and transportation complex and restrict where they can be used.
- Some other chemistries perform better at temperature extremes.
- Nickel based batteries still offer a better cycle life.
- Lead acid batteries remain better at high current applications such as engine starting and powering larger appliances.
- Production costs remain higher than some chemistries like Zinc-Carbon
Until these drawbacks are resolved lithium will not completely replace other battery types.
Types of lithium batteries
- Lithium Metal – primary/disposable (see What are lithium metal batteries for more detail)
- Lithium-ion – secondary/rechargeable (see What are lithium-ion batteries for more detail)
- Lithium-ion Cobalt Oxide – found in most mobile devices and many cameras due to their high specific energy of up to 200Wh/kg.
- Lithium-ion Manganese – more stable than Cobalt Oxide and better at delivering high current this is popular in electric vehicles and power tools although it has a shorter calendar life and cycle life.
- Lithium-ion Iron Phosphate – the safest Lithium-ion battery with a long cycle life and the ability to deliver high current it is ideal for hybrid and stop/start cars but has a very short calendar life.
- Lithium-ion Nickel Cobalt Aluminum Oxide – the best specific energy in this chemistry but costly and with a short cycle life it is only used in some specialist industrial applications.
- Lithium-ion Titanate – operates at very low temperatures but is costly to produce and has low specific energy so it is only found in some specialist applications.
- Lithium-Ion Nickel Manganese Cobalt Oxide – long lasting and excellent at producing high power makes this variant popular in power tools and smaller electric vehicles but does not have a good specific energy.
- Lithium Polymer – secondary/rechargeable – seen as a safer alternative to lithium-ion that can be manufactured even thinner and weigh less but at a higher cost.
- Lithium Sulfur (Li-S) – secondary/rechargeable – a possible replacement to lithium-ion in the future with a cycle life of up to 1,500 and specific energy of up to 500 Wh/Kg but the technology has yet to be commercialized.
- Lithium Air (Li-Air) – secondary/rechargeable – currently more theory than reality but with the possibility to offer a specific energy of over 11,000 Wh/Kg (the same as gasoline and way beyond the 260 Wh/Kg of the best available lithium-ion options). Research is ongoing.
- Lithium Silicon – secondary/rechargeable – also still on the drawing board but attracting research as it could offer specific energy of over 4,000 Wh/Kg which is 15 times better than the best lithium-ion batteries.