Provided is an electrode for a sodium molten-salt battery in which degradation of the electrode can be suppressed even when charging and discharging are repeated, and which has excellent cycle characteristics. The electrode for a sodium molten-salt battery includes a current collector and an electrode mixture adhering to a surface of the current collector, in which the electrode mixture includes an electrode active material and a binder containing a polymer, and the polymer does not contain a fluorine atom. The polymer can include, for example, at least one selected from the group consisting of polyamide resins and polyimide resins or at least one selected from the group consisting of acrylic resins, rubber-like polymers, and cellulose derivatives.

A rechargeable lithium air battery is provided. The battery contains a ceramic separator forming an anode chamber, a molten lithium anode contained in the anode chamber, an air cathode, and a non-aqueous electrolyte. The cathode has a temperature gradient comprising a low temperature region and a high temperature region, and the temperature gradient provides a flow system for reaction product produced by the battery.

Provided is a sodium molten-salt battery having good charge-discharge cycle characteristics. The sodium molten-salt battery includes a positive electrode that contains a positive electrode active material, a negative electrode that contains a negative electrode active material, and a molten-salt electrolyte that contains a sodium salt and an ionic liquid that dissolves the sodium salt. The negative electrode active material contains non-graphitizable carbon. The ionic liquid is a salt of a bis(sulfonyl)imide anion and a first onium cation that does not cause a Faradaic reaction with the non-graphitizable carbon. The molten-salt electrolyte contains a second onium cation in an amount of 1,000 ppm by mass or less. The second onium cation is represented by a general formula (1): R.sup.1R.sup.2R.sup.3R.sup.4N.sup.+ where R.sup.1 to R.sup.4 are each independently a hydrogen atom or a methyl group.

A sodium molten salt battery includes a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator provided between the positive electrode and the negative electrode, and a molten salt electrolyte having sodium ion conductivity, in which the negative electrode active material contains hard carbon and is pre-doped with sodium ions, and in which when the state of charge is 0%, the potential of the negative electrode is 0.7 V or less with respect to metallic sodium.

Provided herein are energy storage devices. In some cases, the energy storage devices are capable of being transported on a vehicle and storing a large amount of energy. An energy storage device is provided comprising at least one liquid metal electrode, an energy storage capacity of at least about 1 MWh and a response time less than or equal to about 100 milliseconds (ms).

The present invention provides rechargeable electrochemical cells comprising a molten anode, a cathode, and a non-aqueous electrolyte salt, wherein the electrolyte salt is situated between the molten anode and the cathode during the operation of the electrochemical cell, and the molten anode comprises an aluminum material; also provided are batteries comprising a plurality of such rechargeable electrochemical cells and processes for manufacturing such rechargeable electrochemical cells.

Cell and batteries containing them employing a cathode having a intercalating metal oxide in combination with a sodium metal haloaluminate. At operating temperatures, the positive electrode (cathode) of the invention comprises electroactive cathode material permeated with and in physical and electrical contact with the sodium metal haloaluminate catholyte. The positive and negative electrodes are separated with a solid alkali metal conducting electrolyte. The intercalating metal oxice is not in direct physical contact with the solid electrolyte. Electric and ionic conductivity between the solid electrolyte and the positive electrode is mediated by the sodium haloaluminate catholyte. Batteries of the invention are useful for bulk energy storage, particularly for electric utility grid storage, as well as for electric vehicle propulsion.

A battery with a corrosion-resistant ion-exchange membrane system is presented. The battery has an acidic catholyte, an anode metal that is chemically reactive towards water, and an ion-exchange membrane system. Some examples of anode metals include alkali metals, alkaline earth metals, and aluminum (Al). The ion-exchange membrane system includes a solid, cation-permeable, water-impermeable first membrane adjacent to the anode, prone to decomposition upon chemical reaction with an acid, an anion-permeable second membrane adjacent to the cathode, and a buffer compartment including a solution, interposed between the first membrane and the second membrane. In response to discharging the battery, the solution in the buffer compartment accepts cations from the anode and anions from the cathode, forming a cation-anion salt solution in the buffer compartment. The second membrane prevents the transportation of protons from the catholyte to the buffer compartment, and so prevents the corrosion of the first membrane.

A molten-salt battery includes a positive electrode including a positive-electrode active material that reversibly occludes and releases sodium, a negative electrode including a negative-electrode active material that reversibly occludes and releases sodium, a separator disposed between the positive electrode and the negative electrode, and a molten-salt electrolyte. The molten-salt electrolyte contains an ionic liquid in an amount of 90% by mass or more. The ionic liquid contains a first salt and a second salt. The first salt contains a sodium ion which is a first cation, and a first anion. The second salt contains an organic cation which is a second cation, and a second anion. The positive-electrode active material contains a composite oxide having a layered O3-type crystal structure and containing Na, Fe, and Co. An amount of Co relative to a total of Fe and Co contained in the composite oxide is 40 to 60 atomic percent.

Provided is a power supply system capable of being used in a well over a long period of time. A power supply system for a well according to the present invention includes a secondary battery having an operating temperature range including a temperature of the inside of a well and supplying power to a device installed in the well; and a charge-discharge mechanism for charging and discharging the secondary battery, and is installed in the well. The secondary battery to be used in the power supply system may be a molten salt battery, and may include a sensor and communication apparatus.