Lithium

Lithium (chemical symbol Li) is a chemical element with atomic number 3. It belongs to the group of alkali metals, which react rapidly with water and air. Lithium is the lightest solid element known; it is less dense than water, and therefore floats on it.

Because of its high reactivity, it does not occur naturally in pure form. It is found in mineral deposits and salt water, particularly in salt brines in arid regions. Its largest current use is in lithium-ion batteries for mobile phones, computers, and electric vehicles.

Physical and chemical properties

Lithium is a soft, silvery metal that can be cut with a knife. When exposed to air, its surface develops a dark tarnish. It is therefore typically stored under oil or in an inert gas. When added to water, it releases hydrogen gas and an alkaline solution. Its flame burns with a carmine-red color, which can be recognized in flame tests.

Sources and extraction

There are two major extraction methods. The first involves extracting lithium-rich brine from underground, which is then concentrated by solar evaporation until lithium levels rise sufficiently, after which it is purified chemically. The second uses mineral ore—particularly spodumene—which is mined, crushed, and processed. Major producing countries include Australia, Chile, Argentina, and China, with China holding a large share of global processing capacity.

Batteries

Lithium-ion batteries operate by the movement of lithium ions between two electrodes. During charging, ions move toward the anode; during discharge, they return. The amount of energy they can store in a small space is why they are chosen for portable devices and electric vehicles. There remain challenges related to fire risk, safety, and recycling.

Other uses

Lithium salts, particularly lithium carbonate, are used in the treatment of bipolar disorder to reduce mood swings. Such use requires regular blood level monitoring, as the margin between an effective dose and a harmful one is narrow. In industry, lithium is added to ceramics and glazes to increase their fire resistance, and to lubricating oils and greases to raise their heat tolerance.