Lithium (Li), the third element on the periodic table, is the lightest known metal. Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions, it is the lightest metal and the least dense solid element.

Lithium is widely distributed on Earth but does not naturally occur in elemental form due to its high reactivity. According to the Handbook of Lithium and Natural Calcium, "Lithium is a comparatively rare element, although it is found in many rocks and some brines, but always in very low concentrations. There are a fairly large number of both lithium mineral and brine deposits, but only comparatively few of them are of actual or potential commercial value. Many deposits are very small; others are too low in grade." At 20 mg lithium per kg of Earth's crust, lithium is the 25th most abundant element. Nickel and lead have the about the same abundance.

The extraction and production of Lithium comes from three primary sources: 1) mining hard rock — ores such as spodumene (which is the most expensive type of lithium production); 2) hectorite clays in the Southwest United States; and 3) brine solutions located under salt beds.

Brines have dominated production, as they represent the lowest cost extraction. According to the U.S Geologic Survey ("USGS"), the global production of Lithium Carbonate Equivalent (LCE) is 128,000 metric tons. Roughly 50% of all production of LCE comes from Chile (63,600 metric tons) and 80% of the global production comes from just four countries (Chile, Argentina, Australia and China). Deposits of lithium are found in South America throughout the Andes mountain chain. Chile is the leading lithium metal producer followed by Argentina; both countries recover the lithium from brines.

Because of its specific heat capacity — the highest of all solids — lithium is often used in coolants for heat transfer applications. In the late 20th century, lithium became important as an anode material. Used in lithium-ion batteries because of its high electrochemical potential, a typical cell can generate approximately 3 volts, compared with 2.1 volts for lead/acid or 1.5 volts for zinc-carbon cells. Because of its low atomic mass, it also has a high charge- and power-to-weight ratio.

What makes lithium attractive in the production of batteries is its unusually high storage capacity, making it the obvious choice for laptop computers, hand held electronic devices and electric vehicle's. Lithium-ion batteries are high energy-density rechargeable batteries. Other rechargeable batteries include the lithium-ion polymer battery, lithium iron phosphate battery, and the nanowire battery.  New technologies are constantly being announced.

Overall demand for lithium is estimated to be growing approximately 5% per year with battery demand increasing over 25% annually. Total lithium carbonate demand is estimated to be approximately 85,000 metric tons/year (2007) predicted to increase to over 200,000 metric tons/year by 2015.