Lithium (Li)

Lithium, an alkali metal, is one of three elements to have been produced during the Big Bang. Lithium is highly reactive, and it has wide-reaching applications, including ceramics, nuclear power and warfare, optics, mental health pharmacology, greases and lubricants, lightweight metal alloys, and air purification.

Overview

Lithium, commonly abbreviated Li, is the element that holds the third position on the periodic table of elements, after helium and before beryllium. Although its name is derived from the Greek word lithos, meaning “stone,” it is a soft metal; the term lithium derives from its discovery as a mineral.

Lithium is a member of the alkali-metal group of elements, a group that also includes sodium, potassium, rubidium, cesium, and francium. All of these elements reside in the first column of the periodic table; one other element exists in the same column: hydrogen, a nonmetal.

Lithium is an abundant element with many applications in modern life, particularly in batteries but also in optics, nuclear weapons, ceramics, air purification, and mental health. The following sections will examine lithium’s chemical and physical properties and a number of its applications.

According to the Big Bang theory, several different nuclei were produced immediately following the Big Bang in a process known as nucleosynthesis, including two stable lithium isotopes, Li-6 and Li-7. Hydrogen and its heavier isotope deuterium also were produced at this time, along with several helium isotopes. Scientists have continued to study the Big Bang nucleosynthesis of lithium and other cosmological processes that create lithium. While researchers were able to make accurate estimates of the amount of other elements created by the Big Bang, they observed less lithium in old stars than they expected to find based on their calculations, a discrepancy which has led to further questions and research about the origins and nature of the universe. In 2020, a National Aeronautics and Space Administration (NASA)-funded study suggested that most of the lithium in the solar system and the galaxy was created by classical novae, the explosion of a white dwarf star that has accumulated gas from a larger star in its orbit.

Lithium was first discovered not in its elemental form but as a salt. Swedish chemist Johan August Arfwedson found lithium in 1817 while analyzing the ore of petalite, a compound that had been discovered in a Swedish mine in 1800. Arfwedson later found lithium in several other elements. Four years later, an English chemist, William Thomas Brande, was the first to isolate elemental lithium; he accomplished this by electrolysis of lithium oxide. In 1855, German chemist Robert Bunsen used electrolysis to isolate lithium from lithium chloride.

Commercial production of lithium did not begin until 1923, when a German company, Metallgesellschaft, began using electrolysis to isolate the element from a molten mixture of two salts, potassium chloride and lithium chloride. The lithium was used to improve Bahnmetall (railway metal), a material the company produced for use in train bearings. In 1932, lithium atoms were transmuted to helium in the world’s first human-made nuclear reaction, setting the stage for lithium’s role in nuclear weapons.

For stockpiling nuclear weapons during the Cold War, the United States became a top producer of lithium. During World War II (1939–45), scientists found that various lithium compounds could be combined to make a grease that worked well to lubricate high-temperature machinery, such as aircraft engines.

The mid-1990s marked the discovery that lithium could be extracted from brine, a much less expensive solution than mining. By the early twenty-first century, the use of lithium-ion batteries was on the rise, propelled by expansions in the green energy sector.

Physical Properties of Lithium

Lithium is a silver-white metal. Under standard temperature and pressure conditions, it is the lightest metal. It also is the least dense element that is not a gas at room temperature (its density is 0.534 gram per cubic centimeter [g/cm³]) and it floats on water and oil. For comparison, water’s density is 1.000 g/cm³.

Lithium rates a 0.6 on the Mohs scale of mineral hardness, softer than even talc, which defines position 1 on the Mohs scale. Lithium is soft enough to be scratched with a fingernail or even cut with a knife, like the other alkali metals, and it yields a shiny metallic surface when cut. Lithium is highly reactive, and the cut surface will quickly tarnish when exposed to moisture in the air. Because it is so reactive, lithium needs to be stored carefully, often in a viscous hydrocarbon, such as petroleum jelly.

Lithium conducts both heat and electricity well, just like its alkali-metal group mates. Among the alkali metals, lithium has the highest melting point (80.54 degrees Celsius, or 356.97 degrees Fahrenheit), but this is low compared with most other metals. Similarly, its boiling point, 1,342 degrees Celcius (2,448 degrees Fahrenheit), is the highest of the alkali metals. Lithium’s specific heat capacity is the highest of all of the solid elements, explaining its usefulness in high-temperature applications such as aircraft engines and train bearings.

Atomic and Chemical Properties of Lithium

Lithium’s atomic number is 3 and its electron configuration is 1S²2S¹, so its first two electrons fill the 1s orbital and its third electron is alone in the 2s orbital. This valence electron readily reacts with other compounds, leaving the cation Li⁺, which explains lithium’s high reactivity and flammability. All alkali metals have just one valence electron, and all are quite reactive, although lithium is actually the least reactive of the group.

In addition to its classification as a group 1 element and an alkali metal, lithium is classified as a period 2 element, which refers to the second row of the periodic table. This period also includes beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neon.

As its final periodic table classification, lithium belongs to the s-block, which includes the alkali metals (most of group 1) and the alkaline earth metals (group 2). In each group within the s-block, most chemical and physical properties move down the column in a trend-like way, so while lithium has the highest boiling point of the alkali metals, sodium has the second highest, followed by potassium, down to francium at the bottom of the column.

Lithium’s high reactivity is especially pertinent in the presence of oxygen and water or even moist air; it can ignite or explode. However, the likelihood is greater with the other alkali metals, which are more reactive than lithium. Generally, under normal temperature and pressure conditions, lithium just tarnishes upon contact with moisture; the reaction produces lithium hydroxide, lithium nitride, and lithium carbonate, the combination of which appears as a dark coating.

Held in a flame, lithium ions cause the flame to appear distinctly crimson as the lithium’s electrons absorb energy from the heat, jump up to higher orbitals, and then fall back down, releasing the extra energy as light (which appears as a visible color). The other metals will produce different colors in the flame test; sodium, for example, yields a bright orange color while potassium yields a lilac or violet color.

The stable Li-7 isotope constitutes about 92.5 percent of naturally occurring lithium, while Li-6 makes up the rest. There are several radioactive isotopes as well, but they are unstable. (The most stable radioactive isotope, Li-8, has a half-life of about 800 milliseconds.) Li-6 plays an important role in nuclear reactors (and nuclear weapons), as it is involved in one of several reactions that can create tritium, a heavy radioactive isotope of hydrogen.

Sources of Lithium

Because it is so reactive, lithium does not occur naturally in its elemental form, only as part of compounds such as salts. Lithium compounds are found virtually everywhere: on land, in the water, within living organisms, and even in outer space. Lithium also can be synthesized commercially by electrolysis of various compounds.

Terrestrially, lithium can be found in the earth’s crust in an abundance of about 70 parts per million, similar to the crustal abundance of nickel and lead. Crustal lithium is most often found in granites, particularly within the pegmatitic crystalline masses that can intrude upon granites. Worldwide, Chile has one of the largest reserves of lithium, approximately 7.5 million tonnes (metric tons), and it mines more than 12,000 more tonnes each year. Bolivia also has several million tonnes of reserves.

Lithium also can be obtained from clays and brines in the ocean, where it is present in an abundance of about 0.25 part per million; the ratio increases to about 7 parts per million around hydrothermal vents on the ocean floor. Extraction of lithium from brine did not begin until the mid-1990s and has proved to be a cheaper alternative to mining.

Lithium was created during the big bang, and about 10 percent of the lithium in the Milky Way galaxy is probably derived from that initial creation. Lithium is still created by stellar nucleosynthesis, which involves nuclear reactions within stars that produce the nuclei of elements. Star-created lithium is found in some red giants, brown dwarfs, and orange stars, and it is possibly a result of the radioactive decay of unstable beryllium-7.

Lithium also is found in trace amounts in many living organisms, including plants and invertebrates and vertebrates. While its physiological role in living organisms is unclear, studies have suggested that it does play a role of some kind.

Use of Lithium in Batteries

Lithium’s most familiar common use is in batteries, especially lithium-ion batteries. Other types of batteries, both rechargeable and disposable, also contain lithium.

Lithium-ion batteries are rechargeable batteries that are prevalent in portable electronics such as mobile phones, and their usage is increasing in other areas, too, such as in electric vehicles. Lithium-ion batteries have several advantages over other batteries. For one, their energy density is efficient, meaning they are able to store large amounts of energy in small amounts of space. They also have a low self-discharge rate; other rechargeable batteries, particularly most models containing nickel, can lose a significant percentage of their charge while not in use because of internal chemical reactions within the battery. Also, lithium-ion batteries do not have the “memory effect” problem of some rechargeable nickel cadmium batteries, in which the total energy capacity of the battery can permanently decrease if the battery is recharged before being fully discharged.

A typical lithium-ion battery has four main components: a positive electrode (made of a metal oxide), a negative electrode (made of carbon, often in the form of graphite), a nonaqueous electrolyte (a lithium salt in an organic solvent), and a separator, which keeps electrons from flowing directly between the electrodes. The positive and negative electrodes can both play the role of either the anode or the cathode, depending on the direction of the current flow through the battery. Commercial production of lithium-ion batteries began in 1991 by the Japanese companies Sony and Asahi Kasei.

Lithium-ion polymer batteries evolved from standard lithium-ion batteries; the main difference involves the electrolyte, which exists in a solid polymer instead of an organic solvent. In the late 2000s, improvements to the design yielded shorter charging times and faster discharge rates, and it is likely that continued improvements will have far-reaching positive implications for electric vehicles, consumer electronics, and other products.

A class of disposable (nonrechargeable) batteries known simply as lithium batteries features an anode made of either a lithium metal or a lithium compound. These batteries have quite long lives (some specialized types can last years) and are used in pacemakers, toys, clocks, cameras, and other devices.

Other Lithium Applications

Aside from batteries, lithium has a wide variety of other applications, such as ceramics, nuclear power and warfare, optics, air purification, greases and lubricants, and even psychiatric medications. By the numbers, the use of lithium compounds in ceramics and glass is actually the biggest use worldwide, even beyond batteries.

As an additive, a lithium compound can reduce melting temperatures of ceramics and glass, decreasing energy costs required in the production of those materials. Lithium also makes the finished product more durable. Lithium is especially important in the production of glass cookware that must not expand as it undergoes temperature changes.

In nuclear power and nuclear weapons, the Li-6 isotope acts as a fusion fuel, aiding in the production of the heavy hydrogen isotope tritium. While this use has dangerous implications as a weapon, it also brings the promise of clean electricity generation in the future.

Lithium makes an appearance in optical equipment in the form of artificially created lithium fluoride crystals, which are transparent and have a low refractive index. They can be used in telescope focal lenses and in other specialized optics applications. In the mental health field, lithium compounds have long been used as mood stabilizers in the treatment of bipolar disorder and various forms of depression.

In enclosed places like spacecraft and submarines, lithium is a useful air purification aid because of its ability to remove carbon dioxide. Lithium also is used in some types of oxygen candles, apparatus that generate oxygen in submarines. Lithium is a useful component of lubricating greases used in high-temperature environments, such as in the engine of an airplane. It also is found in aircraft as part of a variety of lightweight but strong alloys, most often with aluminum.

Lithium technology has seen many advances, particularly regarding lithium-ion batteries and lithium-ion polymer batteries. It remains likely that distinct improvements will be made in the quality of consumer electronics, electric cars, and many other technologies.

Mining and Sustainability

In the first decades of the twenty-first century, lithium mining became increasingly important in a number of industries. The US Geological Survey (USGS) estimated that worldwide lithium reserves amounted to 26 million metric tons in 2023. Amid surging demand for lithium, namely due to its use in rechargeable smartphone and electric vehicle batteries, a number of leading lithium producers, including Australia, Chile, and China, took steps to increase production. At that time, many leading automobile manufacturers around the world had announced plans to stop building gasoline-fueled cars within the next few decades, setting the stage for electric vehicles to become a major driver of increased demand for lithium. Meanwhile, lithium batteries became both cheaper to produce and better-performing than they had been in earlier decades.

While lithium reserves remained plentiful and in fact increased at that time due to increased efforts to discover new reserves, increased lithium mining at this time also raised a number of environmental concerns. At that time, the process of lithium mining itself, whether the lithium was extracted from rock or brine, was incredibly energy-intensive; however, emerging methods of mining, namely the extraction of lithium with geothermal energy, proved more energy-efficient. In a number of South American countries, including Chile, Argentina, and Bolivia, heavy use of water from underground sources contributed to desertification.

In addition to seeking more energy-efficient mining methods, researchers, manufacturers, and activists sought a number of other ways to reduce lithium production's negative footprint. Engineers worked to design batteries which required less metal, and a mix of government agencies, businesses, and other organizations promoted the use of recycled as opposed to newly-mined lithium.

As the presidential administration of Joe Biden attempted to ramp up US lithium production during the early 2020s and promote a clean energy agenda, these efforts were complicated by opposition from many local communities. For example, local mining regulations in Maine prevented extraction of the state's large lithium reserves at that time. By June 2023, some Shoshone communities had halted operations at the massive lithium mine in Thacker Pass, Nevada. These activists cited environmental concerns and argued that these mining operations fit into a long pattern of displacing Indigenous communities in order to extract natural resources.

Principal Terms

alkali metals: soft, shiny, highly reactive metals that readily lose their one valence electron; group 1 of the periodic table of elements

disposable battery: a type of battery, also called a primary cell battery, in which the electrochemical reaction is irreversible and the battery cannot be recharged

electrolysis: a method of separating elements from ores and other sources by using a direct electric current to catalyze a nonspontaneous chemical reaction

flame test: a chemistry test that detects the presence of some metal ions based on the color of the flame when the material in question is held in it; lithium turns a flame crimson

isotopes: variants of an element, both stable and unstable (radioactive); isotopes have the same number of protons but a different number of neutrons

Mohs scale: a scale that characterizes the hardness of minerals based on the ability of one mineral to scratch another

orbitals: imaginary rings around atoms’ nuclei in which electrons can be found; mathematical functions that describe the probable location of electrons relative to an atom’s nucleus

rechargeable battery: a type of battery, also called a secondary cell battery, in which the electrochemical reaction is reversible and the battery can be recharged

salt: an electrically neutral ionic compound; lithium salts consist of lithium cations paired with a variety of anions

stellar nucleosynthesis: a nuclear reaction within a star that results in the production of elemental nuclei heavier than hydrogen

valence electron: an electron that is free to combine with the valence electrons of other atoms, resulting in a bond; in alkali metals and many other elements; only the outermost electrons can be valence electrons

Bibliography

Castelvecchi, Davide. "Electric Cars and Batteries: How Will the World Produce Enough?" Nature, 17 Aug. 2021, www.nature.com/articles/d41586-021-02222-1. Accessed 31 Oct. 2022.

Cough, Kate, and Alana Semuels. "Gem Hunters Found the Lithium America Needs. Maine Won’t Let Them Dig It Up." Time, 17 Jul. 2023, time.com/6294818/lithium-mining-us-maine/. Accessed 2 Aug. 2023.

Dahlin, Greger R., and Kalle E. Strøm. Lithium Batteries: Research, Technology, and Applications. Nova Science, 2010.

Daly, Matthews. "Lithium Dispute on Native Land." ICT News, 24 Jun. 2023, ictnews.org/news/lithium-dispute-on-native-land. Accessed 2 Aug. 2023.

Donnelly, Claire, et al. "The Lithium Boom: What's Holding Back a Lithium Rush in the U.S.?" WBUR, NPR, 11 Mar. 2024, www.wbur.org/onpoint/2024/03/11/lithium-reserves-boom-mining-elements-energy. Accessed 7 Feb. 2025.

Fletcher, Seth. Bottled Lightning: Superbatteries, Electric Cars, and the New Lithium Economy. Hill and Wang, 2011.

Gunn, Alastair. "A Mysterious Force Keeps Destroying the Universe's Lithium. And Scientists Don't Know Why." BBC Science Focus, BBC, 16 June 2023, www.sciencefocus.com/science/lithium-shortage-universe. Accessed 7 Feb. 2025.

Lew, Kristi. The Alkali Metals: Lithium, Sodium, Potassium, Rubidium, Cesium, Francium. Rosen Central, 2010.

McKie, Robin. "Child Labour, Toxic Leaks: The Price We Could Pay for a Greener Future." The Guardian, 3 Jan. 2021, www.theguardian.com/environment/2021/jan/03/child-labour-toxic-leaks-the-price-we-could-pay-for-a-greener-future. Accessed 31 Oct. 2022.

Mineral Commodity Summaries 2025. US Geological Survey, 2025, doi.org/10.3133/mcs2025. Accessed 7 Feb. 2025.

Sutter, Paul M. "Lithium, the Elemental Rebel." Nautilus, 10 Apr. 2024, nautil.us/lithium-the-elemental-rebel-542339/. Accessed 7 Feb. 2025.

Talbert, Tricia. "Lithium Comes from Exploding Stars." NASA, 29 May 2020, www.nasa.gov/universe/lithium-comes-from-exploding-stars/. Accessed 7 Feb. 2025.