Published US 20150104720 to Samsung on lithium/air battery

Abstract of  US 20150104720 :

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A lithium air battery including an anode for intercalating/deintercalating lithium ions; a cathode having oxygen as a cathode active material, a lithium ion conductive solid electrolyte membrane disposed between the anode and the cathode; and an electrolyte, wherein the electrolyte is disposed between the lithium ion conductive solid electrolyte membrane and the cathode, and wherein the electrolyte includes at least one compound selected from a compound represented by Formula 1 and a copolymer including a repeating unit represented by Formula 2 as an additive: ##STR00001## wherein in Formulae 1 and 2, groups CY1, CY2, a, b, c, b, R.sub.1 to R.sub.18, and variables t, u, and v are defined in the specification.

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From the specification:

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[0005] A lithium air battery has been known to include an anode capable of intercalating/deintercalating lithium ions, a cathode having oxygen as a cathode active material and a porous carbon material, and an electrolyte disposed between the cathode and the anode. 

[0006] The lithium air battery uses lithium as an anode, so it is not necessary to store air as a cathode active material within the lithium air battery, thus enabling its high capacity. The theoretical energy density per unit weight of the lithium air battery is very high, for example 3,500 watt hours per kilogram (Wh/kg) or higher. The energy density of the lithium air battery is about 10 times higher than that of a lithium ion battery. 

[0007] However, when a small amount of electrolyte is used to improve permeability of oxygen used as a cathode active material, it is difficult to form a boundary that contacts with air due to the hydrophilic property of the electrolyte and the hydrophobic properties of a porous carbon material included in the cathode, thus lowering the charge/discharge capacity, charge/discharge efficiency, and discharge voltage of a cathode of a lithium air battery. Accordingly, it is desired that a boundary of the electrolyte, and the porous carbon material included in the cathode and oxygen be expanded so that the charge/discharge capacity, charge/discharge efficiency, and discharge voltage of the cathode of the lithium air battery can be improved. Thus, there remains a need in a lithium air battery with improved charge/discharge capacity, charge/discharge efficiency, and discharge voltage of a cathode. 


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