The most well-known contemporary application for lithium is the lithium-ion battery (“LIB”). LIBs are rechargeable batteries used in a wide range of portable electronic devices including mobile phones, tablets, laptop computers and cameras. This battery technology has evolved to the extent that LIBs are now being used in applications with heavy power demands including portable power tools and electric vehicles. Another LIB application is energy storage, which includes the residential energy storage systems that provide power in the home and commonly store energy collected from solar panels on the roof. Non-battery applications include the manufacture of high-temperature resistant and high-strength glasses and ceramics.
Lithium is extracted from two main sources of supply, hard-rock lithium minerals and lithium brines. The world’s lithium production is split roughly evenly between the two. The hard-rock lithium mineral that is most abundant and exploited commercially, predominantly in Australia, is spodumene. Others include Lepidolite and Petalite. Lithium brines typically occur in high mountain basins where inflowing surface and subsurface waters are moderately enriched in soluble salts including lithium. They usually occur in areas with high solar evaporation rates that further concentrate the lithium. Until recently, global lithium supply was dominated by large-scale lithium brine operations that commenced operations in South America (Chile) in the early 1980s.
The schematic below describes the value chain for lithium-ion batteries including the rapidly growing electric vehicle (EV) market.
The most commonly traded processed lithium compounds are the lithium salts: lithium carbonate, lithium hydroxide and lithium chloride. These lithium salts are derived from the lithium-bearing hard-rock minerals and brines and are used as raw materials in many industry applications.
Given the variety of lithium compounds, industry convention is to convert lithium quantities into Lithium Carbonate Equivalent (LCE) units, which is the amount of lithium contained in one tonne of lithium carbonate.
1 tonne LCE
= 1 tonne lithium carbonate (Li2CO3)
= 1.14 tonnes lithium hydroxide (LiOH.H2O)
= ~ 7 tonnes spodumene concentrate (6% Li2O)
Batteries
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.
Lubricating greases
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.
Air treatment
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.
Metallurgy
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.
Polymers
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.
Pharmaceuticals
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
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.
Demand for lithium is currently growing at more than 10% per annum and is projected to continue growing at or near this rate for the next two decades. The sector driving this high rate of growth is the auto battery sector (i.e. EV market), which is currently growing at more than 30% per annum.
Lithium demand is currently being matched by rapid supply growth. In fact, recent new hard-rock mine developments in Australia and capacity expansions by brine producers have exceeded demand growth and the market is reported to be oversupplied at present. This follows a period of very tight market conditions and high prices for raw materials and processed lithium compounds that spurred significant investment in new production capacity.
With further new production capacity being brought into the market over the next few years it is probable that supply will marginally exceed demand until the mid-20s, at which time market conditions will once again support reinvestment in new primary lithium production.
