Disclosed are novel electrolytes, and techniques for making and devices using such electrolytes, which are based on compressed gas solvents. Unlike conventional electrolytes, disclosed electrolytes are based on compressed gas solvents mixed with various salts, referred to as compressed gas electrolytes. Various embodiments of a compressed gas solvent includes a material that is in a gas phase and has a vapor pressure above an atmospheric pressure at a room temperature. The disclosed compressed gas electrolytes can have wide electrochemical potential windows, high conductivity, low temperature capability and/or high pressure solvent properties. Examples of a class of compressed gases that can be used as solvent for electrolytes include hydrofluorocarbons, in particular fluoromethane, difluoromethane, tetrafluoroethane, pentafluoroethane. Also disclosed are battery and supercapacitor structures that use compressed gas solvent-based electrolytes, techniques for constructing such energy storage devices. Techniques for electroplating difficult-to-deposit materials using compressed gas electrolytes as an electroplating bath are also disclosed.

A non-aqueous Magnesium electrolyte comprising: (a) at least one organic solvent; (b) at least one electrolytically active, soluble, inorganic Magnesium (Mg) salt complex represented by the formula: Mg.sub.aZ.sub.bX.sub.c wherein a, b, and c are selected to maintain neutral charge of the molecule, and Z and X are selected such that Z and X form a Lewis Acid, and 1a10, 1b5, and 2c30. Further Z is selected from a group consisting of aluminum, boron, phosphorus, titanium, iron, and antimony; X is selected from the group consisting of I, Br, Cl, F and mixtures thereof. Rechargeable, high energy density Magnesium cells containing an cathode, an Mg metal anode, and an electrolyte of the above-described type are also disclosed.

A non-aqueous Magnesium electrolyte comprising: (a) at least one organic solvent; (b) at least one electrolytically active, soluble, inorganic Magnesium (Mg) salt complex represented by the formula: Mg.sub.aZ.sub.bX.sub.c wherein a, b, and c are selected to maintain neutral charge of the molecule, and Z and X are selected such that Z and X form a Lewis Acid, and 1a10, 1b5, and 2c30. Further Z is selected from a group consisting of aluminum, boron, phosphorus, titanium, iron, and antimony; X is selected from the group consisting of I, Br, Cl, F and mixtures thereof. Rechargeable, high energy density Magnesium cells containing an cathode, an Mg metal anode, and an electrolyte of the above-described type are also disclosed.

Provided is a method for fabricating a magnesium-containing electrode by a plating method. In the fabrication process disclosure, a plating solution used in the plating method includes a solvent containing an ether. The solvent includes a first magnesium salt having a disilazide structure represented by a formula (R.sub.3Si).sub.2N and a second magnesium salt that does not have a disilazide structure. In the formula, R represents a hydrocarbon group having 1 or more and 10 or less carbon atoms.

Provided is a method for fabricating a magnesium-containing electrode by a plating method. In the fabrication process disclosure, a plating solution used in the plating method includes a solvent containing an ether. The solvent includes a first magnesium salt having a disilazide structure represented by a formula (R.sub.3Si).sub.2N and a second magnesium salt that does not have a disilazide structure. In the formula, R represents a hydrocarbon group having 1 or more and 10 or less carbon atoms.

A composite particle comprises a core, a shielding layer deposited on the core, and further comprising an interlayer region formed at an interface of the shielding layer and the core, the interlayer region having a reactivity less than that of the core, and the shielding layer having a reactivity less than that of the interlayer region, a metallic layer not identical to the shielding layer and deposited on the shielding layer, the metallic layer having a reactivity less than that of the core, and optionally, an adhesion metal layer deposited on the metallic layer.

A composite particle comprises a core, a shielding layer deposited on the core, and further comprising an interlayer region formed at an interface of the shielding layer and the core, the interlayer region having a reactivity less than that of the core, and the shielding layer having a reactivity less than that of the interlayer region, a metallic layer not identical to the shielding layer and deposited on the shielding layer, the metallic layer having a reactivity less than that of the core, and optionally, an adhesion metal layer deposited on the metallic layer.

A method for producing a lithium electrode for a lithium-ion battery includes: a) provision of a basic body including an active material having in particular metallic lithium, a lithium alloy, and/or a lithium intercalation material; b) treatment of the basic body with a treatment composition in a wet-chemical process for the formation of a lithium-ion-conducting protective layer, with a reaction of the active material with at least one component of the treatment composition; and c) an optional treatment of the electrode at increased temperature and/or in a vacuum.

A method for producing a lithium electrode for a lithium-ion battery includes: a) provision of a basic body including an active material having in particular metallic lithium, a lithium alloy, and/or a lithium intercalation material; b) treatment of the basic body with a treatment composition in a wet-chemical process for the formation of a lithium-ion-conducting protective layer, with a reaction of the active material with at least one component of the treatment composition; and c) an optional treatment of the electrode at increased temperature and/or in a vacuum.

An anode compartment for rechargeable lithium or sodium batteries, including: a solid electrolyte; a collector deposited on the solid electrolyte; and an active material made of lithium metal or sodium metal which has been grown between the solid electrolyte and the collector in order to form an electrode made of lithium metal or sodium metal with the collector, in which the collector is made of an amorphous alloy. A method for manufacturing such an anode compartment and a battery including said anode compartment is also presented.