Lithium–air battery

The lithium–air battery (Li–air) is a <a href="/facts/Metal%E2%80%93air_electrochemical_cell/P19rjpyH">metal–air electrochemical cell</a> or <a href="/facts/Battery_(electricity)/bqEpm4ue">battery</a> chemistry that uses <a href="/facts/Oxidation/Pyd5RVcj">oxidation</a> of <a href="/facts/Lithium/7vXX6BWA">lithium</a> at the <a href="/facts/Anode/TjYt95zG">anode</a> and <a href="/facts/Redox/Pyd5RVcj">reduction</a> of <a href="/facts/Oxygen/acyn6o8r">oxygen</a> at the <a href="/facts/Cathode/tqdlGayU">cathode</a> to induce a current flow.
Pairing lithium and ambient oxygen can theoretically lead to electrochemical cells with the highest possible <a href="/facts/Specific_energy/zVRhSxPh">specific energy</a>. Indeed, the theoretical specific energy of a non-aqueous Li–air battery, in the charged state with <a href="/facts/Lithium_peroxide/25PAjcsD">Li2O2</a> product and excluding the oxygen mass, is ~40.1 MJ/kg. This is comparable to the theoretical specific energy of gasoline, ~46.8 MJ/kg. In practice, Li–air batteries with a specific energy of ~6.12 MJ/kg lithium at the cell level have been demonstrated. This is about 5 times greater than that of a commercial <a href="/facts/Lithium-ion_battery/3L22xFhB">lithium-ion battery</a>, and is sufficient to run a 2,000 kg <a href="/facts/Electric_vehicle/jhCbx5ur">electric vehicle</a> for ~500 km (310 miles) on a single charge using 60 kg of lithium (i.e. 20.4 kWh/100 km). However, the practical power and <a href="/facts/Cycle_life/vMWrb3q9">cycle life</a> of Li–air batteries need significant improvements before they can find a market niche.
Significant electrolyte advances are needed to develop a commercial implementation. Four approaches are being considered: <a href="/facts/Aprotic/cKJU5bar">aprotic</a>, <a href="/facts/Aqueous_battery/XWccWTFL">aqueous</a>, <a href="/facts/Solid-state_chemistry/MFpqNGSt">solid-state</a> and mixed aqueous–aprotic.
A major market driver for batteries is the automotive sector. The energy density of gasoline is approximately 13 kW·h/kg, which corresponds to 1.7 kW·h/kg of energy provided to the wheels after losses. Theoretically, lithium–air can achieve 12 kW·h/kg (43.2 MJ/kg) excluding the oxygen mass. Accounting for the weight of the full battery pack (casing, air channels, lithium substrate), while lithium alone is very light, the energy density is considerably lower.

Lithium–air battery open-in-new

Lithium–air battery