Rechargeable lithium-air and other lithium-based batteries using molten nitrates

A rechargeable molten nitrate salt electrolyte battery, comprising:

• a) an electrolyte comprising lithium nitrate which electrolyte is capable upon being heated above its melting point of becoming an ionically conductive liquid containing lithium ions and nitrate ions, the lithium nitrate being present at a level sufficient to provide stability for a protective solid electrolyte interface formed on lithium metal on contact with the electrolyte,
• b) an anode comprising lithium immersed in the electrolyte, the anode and the electrolyte being compatible with each other for introducing lithium ions into the electrolyte and having a stable layer of lithium oxide serving as the solid electrolyte interface formed on the surface of the lithium in contact with the electrolyte,
• c) a cathode electrode immersed in the electrolyte comprising an electrically conductive surface that is compatible with the electrolyte and capable of transferring electrical charge to or from chemical compounds, namely nitrate ions and oxygen, present within the electrolyte,
• d) oxygen atoms present within the electrolyte in the form of nitrate ions to serve as an internal source of oxygen within the electrolyte for providing oxygen atoms to be delivered, when the electrolyte is at a temperature above its melting point, through the electrolyte to the cathode electrode for reaction at the cathode whereby during battery discharge one or more lithium oxides are formed,
• e) electrical connections respectively present on the anode and cathode and electrically connected to the lithium in the anode and the electrically conductive surface of the cathode electrode for connecting the battery to an external circuit which will allow current to flow through the battery in conjunction with electrochemical reactions occurring at the anode and cathode electrode,
• f) a diffuser of external oxygen positioned within the electrolyte to introduce into the electrolyte oxygen gas from an external oxygen source to provide the direct reduction of the oxygen at the cathode as well as the reduction of the oxygen by a homogeneous chemical reaction with nitrite ions present in the electrolyte to form nitrate ions, and
• g) surfaces within the cell electrolyte for collecting lithium oxide formed during battery discharge, said surfaces being electrically connected to the cathode electrode for the lithium oxide to be dissociated into lithium ions and oxygen during battery recharging,
• wherein, when operated as a battery, the anode and cathode reactions are reversible in accordance with the polarity of the current flowing through the battery thereby providing a molten salt electrolyte battery which is rechargeable.