page_title: Lithium–air battery
section_title: Aqueous
hierarchical_section_title: Lithium–air battery / Design and operation / Electrolyte / Aqueous
caption_attribution_description: English: Schematic of a mixed aqueous-aprotic type Li-air battery design
context_page_description: The lithium–air battery is a metal–air electrochemical cell or battery chemistry that uses oxidation of lithium at the anode and reduction of oxygen at the cathode to induce a current flow.
  Pairing lithium and ambient oxygen can theoretically lead to electrochemical cells with the highest possible specific energy. Indeed, the theoretical specific energy of a non-aqueous Li–air battery, in the charged state with Li₂O₂ 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 at the cell level have been demonstrated. This is about 5 times greater than that of a commercial lithium-ion battery, and is sufficient to run a 2,000 kg EV for ~500 km on one charge using 60 kg of batteries. However, the practical power and life-cycle 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 active: aprotic, aqueous, solid state and mixed aqueous–aprotic.
context_section_description: An aqueous Li–air battery consists of a lithium metal anode, an aqueous electrolyte and a porous carbon cathode. The aqueous electrolyte combines lithium salts dissolved in water. It avoids the issue of cathode clogging because the reaction products are water-soluble. The aqueous design has a higher practical discharge potential than its aprotic counterpart. However, lithium metal reacts violently with water and thus the aqueous design requires a solid electrolyte interface between the lithium and electrolyte. Commonly, a lithium-conducting ceramic or glass is used, but conductivity are generally low (on the order of 10⁻³ S/cm at ambient temperatures).
caption: Schematic of a mixed aqueous–aprotic type Li–air battery design
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