Provided are solid-state electrolyte structures. The solid-state electrolyte structures are ion-conducting materials. The solid-state electrolyte structures may be formed by 3-D printing using 3-D printable compositions. 3-D printable compositions may include ion-conducting materials and at least one dispersant, a binder, a plasticizer, or a solvent or any combination of one or more dispersant, binder, plasticizer, or solvent. The solid-state electrolyte structures can be used in electrochemical devices.

A novel high cycle life, low cost hybrid redox flow battery that has application in the storage of energy generated by solar cells, windmills and other means is described. By combining a solid battery positive electrode with a redox flow negative electrode, the volumetric energy density of the system is maximized and footprint minimized for medium scaled installations of multi kilowatt-hour size as may be envisioned in domestic distributed power systems. The positive electrode is a high cycle life rechargeable nickel hydroxide electrode in alkaline solution. The negative active material is a low cost organic chemical such as a substituted anthroquinone dissolved in an alkaline electrolyte and stored external to the negative plate of the electrochemical device. The material of the negative plate is high surface area and capable of facilitating the oxidation and reduction reactions of the negative active material. The negative and positive electrodes are separated by an electronically insulating but ionically conducting separator material that allows ionic mobility and the generation of electric current when charging or discharging of the battery takes place. Ideally, an ion exchange membrane would separate the positive and negative active material in order to maximize service life and reduce intermingling of active material.

Provided are capacitor-assisted lithium batteries (CAB), comprising an electrolyte comprising one or more lithium salts, and one or more sulfone molecules, wherein the one or more sulfone molecules comprise sulfolane, a substituted sulfolane, and/or a substituted SO.sub.2. The electrolyte may further include one or more solvents. The sulfone-based electrolyte inhibits or prevents undesired gas generation.

A hybrid lithium-ion battery/capacitor cell comprising at least a pair of graphite anodes assembled with a lithium compound cathode and an activated carbon capacitor electrode can provide useful power performance properties and low temperature properties required for many power utilizing applications. The graphite anodes are formed of porous layers of graphite particles bonded to at least one side of current collector foils which face opposite sides of the activated carbon capacitor. The porous graphite particles are pre-lithiated to form a solid electrolyte interface on the anode particles before the anodes are assembled in the hybrid cell. The pre-lithiation step is conducted to circumvent the irreversible reactions in the formation of a solid electrolyte interface (SEI) and preserve the lithium content of the electrolyte and lithium cathode during formation cycling of the assembled hybrid cell. The pre-lithiation step is also applicable to other anode materials that benefit from such pre-lithiation.

Provided herein are devices comprising one or more cells, and methods for fabrication thereof. The devices may be electrochemical devices. The devices may include three-dimensional supercapacitors. The devices may be microdevices such as, for example, microsupercapacitors. In some embodiments, the devices are three-dimensional hybrid microsupercapacitors. The devices may be configured for high voltage applications. In some embodiments, the devices are high voltage microsupercapacitors. In certain embodiments, the devices are high voltage asymmetric microsupercapacitors. In some embodiments, the devices are integrated microsupercapacitors for high voltage applications.

Provided herein are devices comprising one or more cells, and methods for fabrication thereof. The devices may be electrochemical devices. The devices may include three-dimensional supercapacitors. The devices may be microdevices such as, for example, microsupercapacitors. In some embodiments, the devices are three-dimensional hybrid microsupercapacitors. The devices may be configured for high voltage applications. In some embodiments, the devices are high voltage microsupercapacitors. In certain embodiments, the devices are high voltage asymmetric microsupercapacitors. In some embodiments, the devices are integrated microsupercapacitors for high voltage applications.

In a method for balancing an energy storage system, a capacitance of capacitive storage modules of a series circuit of capacitive storage modules is determined. The capacitive storage modules are connected to a balancing device to allow control of a charge of each of the capacitive storage modules via a flow of current between the balancing device and the capacitive storage modules. For each of the capacitive storage modules a module charge is determined from a voltage of the capacitive storage module and a predefined balancing voltage. A reference charge is determined from the module charges of the capacitive storage modules, and a balancing charge is determined for each of the capacitive storage modules from the reference charge and the module charge of the capacitive storage module. The charge of the capacitive storage modules is controlled by exchanging the balancing charge between the capacitive storage module and the balancing device.

An electric energy storage device has first and second conductor layers, a plastic sheet, a quantum dot, and positive and negative electrodes wherein the first and second conductor layers has surfaces coated with ionic or dipole material. The first conductor layer is stacked on top of the second conductor layer with a nanometer-scale interval and with the ionic material layer inbetween, forming a bilayer structure and a quantum heterostructure. Millions of bilayers are stacked together to form a multilayer structure. A positive electrode is attached to the first conductor layer and a negative electrode is attached to the last conductor layer, wherein the first and second conductor layers store electrical energy in the bilayer in a form of binding energy.

An electrochemical energy storage device includes an anode having a first mixture which includes a first plurality of electrically conductive carbon-comprising particles having a first average porosity, and lithium metal materials. The weight ratio of the first plurality of carbon-comprising and lithium metal materials is from 30:1 to 3:1. A cathode includes a second mixture having a second plurality of electrically conductive carbon-comprising particles having a second average porosity greater than the first average porosity, and lithium-intercalating metal oxide particles. The weight ratio of the second plurality of carbon-comprising and lithium-intercalating metal oxide particles is from 1:20 to 5:1. The weight ratio between the lithium metal materials loaded in the anode and the second plurality of carbon-comprising particles in the cathode is from 0.1-10%. An electrolyte physically and ionically contacts the anode and the cathode, and fills the pore volume in the anode, cathode and a porous separator.

An electrochemical energy storage device includes an anode having a first mixture which includes a first plurality of electrically conductive carbon-comprising particles having a first average porosity, and lithium metal materials. The weight ratio of the first plurality of carbon-comprising and lithium metal materials is from 30:1 to 3:1. A cathode includes a second mixture having a second plurality of electrically conductive carbon-comprising particles having a second average porosity greater than the first average porosity, and lithium-intercalating metal oxide particles. The weight ratio of the second plurality of carbon-comprising and lithium-intercalating metal oxide particles is from 1:20 to 5:1. The weight ratio between the lithium metal materials loaded in the anode and the second plurality of carbon-comprising particles in the cathode is from 0.1-10%. An electrolyte physically and ionically contacts the anode and the cathode, and fills the pore volume in the anode, cathode and a porous separator.