30-second summary
Lithium Metal Battery
Lithium-based primary cells are non-rechargeable batteries that have metallic lithium as an anode. These types of batteries are also referred to as lithium-metal batteries.
Primary lithium batteries have the lowest self-discharge rate hence the longest available shelf time, up to 10 years, and in temperatures up to 70.
The most common cells are summarized below:
- Lithium-Manganese Dioxide Cell.
- Lithium Iron Disulphide Cell.
- Lithium Thionyl Chloride Cell.
- Lithium Air Cell.
Overall reaction (Li/MnO2 cells):
Li(s) + MnIVO2(s) ⇌ MnIIIO2(Li+) [E° = +3.19 V]
Lithium Metal Battery
Lithium-based primary cells are batteries that have metallic lithium as an anode. These types of batteries are also referred to as lithium-metal batteries. Note that disposable primary lithium batteries must be distinguished from secondary lithium-ion or lithium-polymer, which are rechargeable batteries. Lithium-ion batteries do not contain metallic lithium.
Primary lithium batteries have the lowest self-discharge rate hence the longest available shelf time, up to 10 years, and in temperatures up to 70. The first letter in the IEC standard system identifies the battery’s chemical composition. C is for lithium metal batteries (as CR2032). The characteristics that make lithium an exceptional electrode material for high energy density batteries include low electrode potential and very high conductivity. It is soft and malleable and can be extruded into thin foils.
They may be classified in several ways, but one convenient method is by the cathode material and voltage. Using an iron disulfide cathode gives a battery with a nominal voltage of 1.5 volts. This cell is used for high-performance AA batteries. Most other lithium batteries are 3.0 volt systems using cathodes comprising either solids (manganese dioxide or carbon monofluoride) or highly toxic liquids (sulfur dioxide or thionyl chloride).
Types of Lithium Metal Batteries
The most common cells are summarized below:
- Lithium-Manganese Dioxide Cell. This cell uses lithium foil as the anode and manganese dioxide as the cathode. The electrolyte is a separator sheet impregnated with electrolytic salts. The overall cell voltage is 3 volts. It is the most common non-rechargeable lithium cell commonly used in button cells like CR2032.
- Lithium Iron Disulphide Cell. Cylindrical lithium iron disulfide batteries (LiFeS2) use lithium for the anode, iron disulfide for the cathode, and a lithium salt in an organic solvent blend as the electrolyte. Designed to be a drop-in replacement for Zinc-carbon or alkaline batteries, the cell voltage is 1.5 volts. They are often called “voltage-compatible” lithium cells. They have a higher energy density than the cells they replace and are tailored to high current applications. They are also produced in the AA battery format.
- Lithium Thionyl Chloride Cell. This type of cell has the highest energy density of all lithium-type cells and has a service life of 15 to 20 years.
- Lithium Air Cell. Similar to zinc-air cells, they have a very high theoretical energy density. The anode, a metallic lithium foil pressed into a nickel mesh current collector, is electrochemically coupled to an unlimited supply of atmospheric oxygen through an air cathode.
Disposable primary lithium batteries must be distinguished from secondary lithium-ion or lithium-polymer, which are rechargeable batteries.
Composition of Lithium Metal Battery
The lithium metal battery (Li/MnO2 cell) consists of five parts:
- Lid (negative terminal)
- Anode. The active material in the anode is metallic lithium. Li+ ions go into the solution and diffuse through the electrolyte and separator to the cathode.
- Separator. A separator is a permeable membrane placed between a battery’s anode and cathode.
- Cathode. The active material of the cathode is high-density manganese dioxide (MnO2). The MnO2 is reduced from the tetravalent to the trivalent state.
- Electrolyte. The electrolyte in Li/MnO2 cells is an organic solvent mixture into which an alkali metal salt is dissolved.
- Can (positive terminal)
