Lithium is used in several different types of batteries, both non-rechargeable and rechargeable. This is because lithium has properties that make it ideal for battery applications. It is the lightest metal (i.e. has the lowest density), it is the most electronegative metal and it has excellent electrical conductivity.
In non-rechargeable batteries (i.e. disposable batteries) the anode (i.e. negative electrode) is often made from lithium metal, which is produced electrolytically from lithium chloride. These batteries have a longer life than most other types of disposable battery but tend to be more expensive. They are often used for applications where long life is important including medical device implants such as pacemakers. They are also used in watches, clocks and cameras where they have the advantage of reduced size compared to other types of battery.
Rechargeable batteries are commonly lithium-ion batteries. In these batteries the lithium is present in the electrolyte and cathode (i.e. positive electrode). Lithium ions move from the anode through the electrolyte to the cathode during use (i.e. discharging) and move in the opposite direction during charging. The anode is typically made of carbon in the form of graphite. The electrolyte often contains lithium hexafluorophosphate. The cathode can be any one of a number of lithium chemistries including lithium-cobalt-oxide (LCO), lithium-manganese-oxide (LMO), nickel-cobalt-aluminium (NCA), lithium-iron-phosphate (LFP), nickel-manganese-cobalt (NMC), lithium titanate (LTO), lithium sulphur (LiS) or lithium polymer. Lithium carbonate and lithium hydroxide are the lithium compounds used in the production of these precursor materials.
Ceramics and glass
Traditionally, the largest markets for lithium have been the ceramics and glass markets. In these applications, lithium in the form of either lithium mineral concentrate or lithium carbonate is used as a flux to reduce the melting point and viscosity of the silica-based glasses and ceramics. This saves energy and reduces costs for producers. Lithium has a low coefficient of thermal expansion, which means that it expands very little as the temperature rises. Glass and ceramic glazes containing lithium are more resistant to higher temperatures. Consequently, products such as ceramic glass cooktops and cookware are able to withstand large and rapid changes in temperature. Glass containing lithium is also more resistant to chemical attack and has improved hardness and shine.
Lithium-ion batteries have advantages over other types of rechargeable battery because they are lighter, have a high energy density (i.e. they produce more energy per unit of weight), they hold their charge better and they have no memory effect, which means they do not have to be completely discharged before recharging.
A lubricating grease is a type of lubricating fluid that has been combined with a thickening agent to ensure the lubricant is more easily retained where it is needed. Lithium hydroxide is used to produce lithium grease, which is one of the most common lubricating greases owing to its performance and cost effectiveness.
Lithium bromide and lithium chloride are both hygroscopic and are used as desiccants for gas streams, for example in air conditioning systems. Lithium hydroxide and lithium peroxide are used to remove carbon dioxide in enclosed spaces such as submarines and spacecraft by converting it to lithium carbonate. Lithium peroxide is particularly useful in these applications because it releases oxygen during the process.
Lithium-bearing powders, which are commonly produced from lithium mineral concentrates, are used as mould fluxes for the continuous casting of steel and as anti-veining additives in mould sands used in the manufacture of cast metal products. In these applications, owing to lithium’s low thermal expansion coefficient, the lithium-bearing powders help to reduce or eliminate surface defects in the cast metals.
Organolithium compounds, including butyllithium, are used in the production of polymers including synthetic rubber and plastics. For example, alkyl lithium compounds are used as olymerization initiators in the production of elastic polymers such as styrene butadiene rubber, which is widely used to make car tyres.
A number of lithium compounds, including lithium carbonate, are used in medicine as mood-stabilising drugs or for the treatment of bipolar disorder. Lithium is sometimes used in conjunction with other substances for other psychiatric disorders.
Aluminium metal is produced by the electrolytic reduction of alumina which is dissolved in a cryolite bath. The addition of lithium carbonate to this bath reduces its melting point, thereby saving both energy and cost.