The present disclosure provides an energy storage device comprising at least one electrochemical cell comprising a negative current collector, a negative electrode in electrical communication with the negative current collector, an electrolyte in electrical communication with the negative electrode, a positive current collector, and a positive electrode in electrical communication with the positive current collector and electrolyte. The positive electrode comprises a material that is solid at the operating temperature of the energy storage device.

The present disclosure provides an energy storage device comprising a negative electrode, a molten electrolyte in electrical communication with the negative electrode, and a positive electrode in electrical communication with the molten electrolyte. One or more of the negative electrode, positive electrode, and molten electrolyte may be at least partially liquid at an operating temperature of the energy storage device. The positive electrode may be at least partially solid at the operating temperature of the energy storage device.

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).

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 disclosure provides seals for devices that operate at elevated temperatures and have reactive metal vapors, such as lithium, sodium or magnesium. In some examples, such devices include energy storage devices that may be used within an electrical power grid or as part of a standalone system. The energy storage devices may be charged from an electricity production source for later discharge, such as when there is a demand for electrical energy consumption.

An interfacial additive layer for decreasing the interfacial resistance/impedance of a silicon based electrode-containing device such as, for example, an energy storage device or a micro-resistor, is disclosed. The interfacial additive layer, which is composed of a molten lithium containing salt, is formed between a silicon based electrode and a solid polymer electrolyte layer of the device. The presence of such an interfacial additive layer increases the ion and electron mobile dependent performances at the silicon based electrode interface due to significant decrease in the resistance/impedance that is observed at the respective interface as well as the impedance observed in the bulk of the device.

A rechargeable, self-heating aluminum-chalcogen battery is provided, with an aluminum or aluminum alloy negative electrode, a positive electrode of elemental chalcogen, and a mixture of chloride salts providing a molten salt electrolyte. The predominant chloride salt in the electrolyte is AlCl.sub.3. Additional chloride salts are chosen from alkali metal chlorides. The cell operates at a modestly elevated temperatures, ranging from 90° C. to 250° C.

Disclosed herein are methods and systems for monitoring and/or regulating energy storage devices. Examples of such monitoring and/or regulating include cell balancing, dynamic impedance control, breach detection and determination of state of charge of energy storage devices.

A positive electrode composition is described, containing granules of at least one electroactive metal, at least one alkali metal halide and carbon black. An energy storage device and an uninterruptable power supply device are also described. Related methods for the preparation of a positive electrode and an energy storage device are also disclosed.

A dense β″-alumina/zirconia composite solid electrolyte and process for fabrication are disclosed. The process allows fabrication at temperatures at or below 1600° C. The solid electrolytes include a dense composite matrix of β″-alumina and zirconia, and one or more transition metal oxides that aid the conversion and densification of precursor salts during sintering. The composite solid electrolytes find application in sodium energy storage devices and power-grid systems and devices for energy applications.