An aqueous lithium-ion battery is a lithium-ion battery (Li-ion) that uses a concentrated saline solution as an electrolyte to facilitate the transfer of lithium ions between electrodes and induce an electrical current.[1] In contrast to non-aqueous lithium-ion batteries, aqueous Li-ion batteries are nonflammable and do not pose any significant risks of explosion, because of the water-based nature of their electrolyte. They also lack the poisonous chemicals and environmental risks associated with their non-aqueous counterparts.[2][3]
Aqueous Li-ion batteries are currently severely limited in use due to their narrow electrochemical window of stability (1.23 V). When built using conventional methods, an aqueous Li-ion has a much smaller energy density than a non-aqueous Li-ion battery and can only reach a maximum voltage of 1.5 volts. However, researchers from the University of Maryland (UMD) and the Army Research Laboratory (ARL) made it possible for an aqueous Li-ion battery to remain electrochemically stable at approximately 3.0 volts and withstand severe external damage to a degree not present in non-aqueous Li-ion batteries.[3]