Is lithium the new gold?

Although it has been known for almost two centuries, lithium is suddenly making the news: it is the primary ingredient of the lithium-ion batteries set to power the next generation of electric vehicles and, as such, could become as precious as gold in this century1. It is also non-uniformly spread within the Earth’s crust, sparking rumours that Andean South American countries could soon be the ‘new Middle-East’. Together, these factors set the scene for controversial debates about the available reserves2–4 and the anticipated demands1: if all cars are to become electric within 50 years, fears of a crunch in lithium resources — and thus a staggering price increase such as that faced today with fossil fuels — are permeating. With its atomic number of 3, lithium is located in the top left corner of the periodic table. It was Johann August Arfvedson, one of Jöns Jakob Berzelius’s students, who first detected its presence in 1817 while analysing the mineral petalite (LiAlSi4O10), itself discovered in 1800. Berzelius called this new element lithos (Greek word for stone). Lithium, whose silvery-white colour tarnishes on oxidation when exposed to air, is the most electropositive metal (−3.04 V versus a standard hydrogen electode), the lightest (M = 6.94 g mol–1) and the least dense (ρ = 0.53 g cm–3) solid element at room temperature, and is also highly flammable. Owing to this high reactivity, lithium is present only in compounds in nature — either in brines or hard rock minerals — and must be stored under anhydrous atmospheres, in mineral oil or sealed evacuated ampoules. Their particular physical, chemical and electrochemical properties make lithium and its compounds attractive to many fields. Apart from the recent advent of lithiumbased batteries, lithium niobate (LiNbO3) is an important material in nonlinear optics. Engineers use lithium in hightemperature lubricants, to strengthen alloys, and for heat-transfer applications. It is also widespread in the fine chemical industry, as organo-lithium reagents are extremely powerful bases and nucleophiles used to synthesize many chemicals. Its effect on the nervous system has also made lithium attractive as a mood-stabilizing drug, and in nuclear research tritium (3H) is obtained by irradiating 6Li. Annual demand has therefore grown by 7–10%, currently reaching about 160,000 tons of lithium carbonate (Li2CO3) per year — about 20–25% of which is for the battery sector.