Abstract: Provided herein are nanostructure networks having high energy storage, electrochemically active electrode materials including nanostructure networks having high energy storage, as well as electrodes and batteries including the nanostructure networks having high energy storage. According to various implementations, the nanostructure networks have high energy density as well as long cycle life. In some implementations, the nanostructure networks include a conductive network embedded with electrochemically active material. In some implementations, silicon is used as the electrochemically active material. The conductive network may be a metal network such as a copper nanostructure network. Methods of manufacturing the nanostructure networks and electrodes are provided. In some implementations, metal nanostructures can be synthesized in a solution that contains silicon powder to make a composite network structure that contains both.

Abstract: Provided are electrode layers for use in rechargeable batteries, such as lithium ion batteries, and related fabrication techniques. These electrode layers have interconnected hollow nanostructures that contain high capacity electrochemically active materials, such as silicon, tin, and germanium. In certain embodiments, a fabrication technique involves forming a nanoscale coating around multiple template structures and at least partially removing and/or shrinking these structures to form hollow cavities. These cavities provide space for the active materials of the nanostructures to swell into during battery cycling. This design helps to reduce the risk of pulverization and to maintain electrical contacts among the nanostructures. It also provides a very high surface area available ionic communication with the electrolyte. The nanostructures have nanoscale shells but may be substantially larger in other dimensions.

Abstract: Provided are novel electrode material composite structures containing high capacity active materials formed into porous base structures. The structures also include shells that encapsulate these porous base structures. During lithiation of the active material, the shell mechanically constrains the porous base structure. The shell allows lithium ions to pass through but prevents electrolyte solvents from interacting with the encapsulated active material. In certain embodiments, the shell contains carbon, while the porous base structure contains silicon. Although silicon tends to swell during lithiation, the porosity of the base structure and/or void spaces inside the shell helps to accommodate this additional volume within the shell without breaking it or substantially increasing the overall size of the composite structure.

Abstract: Provided are novel multidimensional electrode structures containing high capacity active materials for use in rechargeable electrochemical cells. These structures include main support structures and multiple nanowires attached to the support structures and extending into different directions away from these supports. The active material may be deposited as a layer (uniform or non-uniform) surrounding the nanowires and, in certain embodiments, the main supports and even substrate. The active material layer may be sufficiently thin to prevent pulverization of the layer at given operating conditions. Interconnections between the electrode structures and/or substrate may be provided by overlaps formed during deposition of the active layer. Silicide-based nano wires structures may be formed on the main supports in a fluidized bed reactor by suspending the metal-containing main supports in a silicon-containing process gas. A layer of silicon may be then deposited over these silicide nanowires.

Abstract: Provided are examples of electrochemically active electrode materials, electrodes using such materials, and methods of manufacturing such electrodes. Electrochemically active electrode materials may include a high surface area template containing a metal silicide and a layer of high capacity active material deposited over the template. The template may serve as a mechanical support for the active material and/or an electrical conductor between the active material and, for example, a substrate. Due to the high surface area of the template, even a thin layer of the active material can provide sufficient active material loading and corresponding battery capacity. As such, a thickness of the layer may be maintained below the fracture threshold of the active material used and preserve its structural integrity during battery cycling.

Abstract: Provided are novel electrolytes for use in rechargeable lithium ion cells containing high capacity active materials, such as silicon, germanium, tin, and/or aluminum. These novel electrolytes include one or more pyrocarbonates and, in certain embodiments, one or more fluorinated carbonates. For example, dimethyl pyrocarbonate (DMPC) may be combine with mono-fluoroethylene carbonate (FEC). Alternatively, DMPC or other pyrocarbonates may be used without any fluorinated carbonates. A weight ratio of pyrocarbonates may be between about 0% and 50%, for example, about 10%. Pyrocarbonates may be combined with other solvents, such as ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and/or ethyl-methyl carbonate (EMC). Alternatively, pyrocarbonates may be used without such solvents.

Abstract: Provided are novel methods of fabricating electrochemical cells containing high capacity active materials that form multilayered solid electrolyte interphase (SEI) structures on the active material surface during cell fabrication. Combining multiple different SEI layers on one surface can substantially improve cell performance by providing each layer with different properties. For example, an outer layer having a high electronic resistance may be combined with an inner layer having a high ionic permeability. To form such multilayered SEI structures, formation may involve changing electrolyte composition, functionalizing surfaces, and/or varying formation conditions. For example, formation may start with a boron containing electrolyte. This initial electrolyte is then replaced with an electrolyte that does not contain boron and instead may contain fluorine additives. In certain embodiments, cell's temperature is changed during formation to initiate different chemical reactions during SEI formation.

Abstract: Apparatuses and methods for depositing materials on both side of a web while it passes a substantially vertical direction are provided. In particular embodiments, a web does not contact any hardware components during the deposition. A web may be supported before and after the deposition chamber but not inside the deposition chamber. At such support points, the web may be exposed to different conditions (e.g., temperature) than during the deposition.

Abstract: Provided are novel negative electrodes for use in lithium ion cells. The negative electrodes include one or more high capacity active materials, such as silicon, tin, and germanium, and a lithium containing material prior to the first cycle of the cell. In other words, the cells are fabricated with some, but not all, lithium present on the negative electrode. This additional lithium may be used to mitigate lithium losses, for example, due to Solid Electrolyte Interphase (SEI) layer formation, to maintain the negative electrode in a partially charged state at the end of the cell discharge cycle, and other reasons. In certain embodiments, a negative electrode includes between about 5% and 25% of lithium based on a theoretical capacity of the negative active material. In the same or other embodiments, a total amount of lithium available in the cell exceeds the theoretical capacity of the negative electrode active material.

Abstract: Provided are methods of preparing a lithium ion cell including forming the cell by charging the lithium ion cell to at least about 5% or, more specifically, to at least about 20% of the theoretical capacity of the negative electrode electrochemically active material, holding the lithium ion cell in a charged state for at least about 0.5 hours, and discharging the lithium ion cell. Holding the lithium ion cell in a partially charged state is believed to significantly improve its Coulombic efficiency during subsequent cycling.

Abstract: Provided are conductive substrates having open structures and fractional void volumes of at least about 25% or, more specifically, or at least about 50% for use in lithium ion batteries. Nanostructured active materials are deposited over such substrates to form battery electrodes. The fractional void volume may help to accommodate swelling of some active materials during cycling. In certain embodiments, overall outer dimensions of the electrode remain substantially the same during cycling, while internal open spaces of the conductive substrate provide space for any volumetric changes in the nanostructured active materials. In specific embodiments, a nanoscale layer of silicon is deposited over a metallic mesh to form a negative electrode. In another embodiment, a conductive substrate is a perforated sheet with multiple openings, such that a nanostructured active material is deposited into the openings but not on the external surfaces of the sheet.

Abstract: Provided are examples of electrochemically active electrode materials, electrodes using such materials, and methods of manufacturing such electrodes. Electrochemically active electrode materials may include a high surface area template containing a metal silicide and a layer of high capacity active material deposited over the template. The template may serve as a mechanical support for the active material and/or an electrical conductor between the active material and, for example, a substrate. Due to the high surface area of the template, even a thin layer of the active material can provide sufficient active material loading and corresponding battery capacity. As such, a thickness of the layer may be maintained below the fracture threshold of the active material used and preserve its structural integrity during battery cycling.

Abstract: Provided are electrode layers for use in rechargeable batteries, such as lithium ion batteries, and related fabrication techniques. These electrode layers have interconnected hollow nanostructures that contain high capacity electrochemically active materials, such as silicon, tin, and germanium. In certain embodiments, a fabrication technique involves forming a nanoscale coating around multiple template structures and at least partially removing and/or shrinking these structures to form hollow cavities. These cavities provide space for the active materials of the nanostructures to swell into during battery cycling. This design helps to reduce the risk of pulverization and to maintain electrical contacts among the nanostructures. It also provides a very high surface area available ionic communication with the electrolyte. The nanostructures have nanoscale shells but may be substantially larger in other dimensions.

Abstract: Provided are examples of electrochemically active electrode materials, electrodes using such materials, and methods of manufacturing such electrodes. Electrochemically active electrode materials may include a high surface area template containing a metal silicide and a layer of high capacity active material deposited over the template. The template may serve as a mechanical support for the active material and/or an electrical conductor between the active material and, for example, a substrate. Due to the high surface area of the template, even a thin layer of the active material can provide sufficient active material loading and corresponding battery capacity. As such, a thickness of the layer may be maintained below the fracture threshold of the active material used and preserve its structural integrity during battery cycling.

Abstract: Provided are electrode layers for use in rechargeable batteries, such as lithium ion batteries, and related fabrication techniques. These electrode layers have interconnected hollow nanostructures that contain high capacity electrochemically active materials, such as silicon, tin, and germanium. In certain embodiments, a fabrication technique involves forming a nanoscale coating around multiple template structures and at least partially removing and/or shrinking these structures to form hollow cavities. These cavities provide space for the active materials of the nanostructures to swell into during battery cycling. This design helps to reduce the risk of pulverization and to maintain electrical contacts among the nanostructures. It also provides a very high surface area available ionic communication with the electrolyte. The nanostructures have nanoscale shells but may be substantially larger in other dimensions.

Abstract: Provided herein are novel template electrode materials and structures for lithium ion cells. Related methods are also provided. According to various embodiments, an electrode can include a nanostructured template, an electrochemically active material layer coating the template, and a first intermediate layer between the nanostructured template and the electrochemically active material layer. In one arrangement, the nanostructured template includes silicide nanowires. The electrochemically active material may be any of silicon, tin, germanium, carbon, metal hydrides, silicides, phosphides, and nitrides. The first intermediate layer may facilitate adhesion between the nanostructured template and the electrochemically active material layer, electronic conductivity within the electrode, and/or stress relaxation between the nanostructured template and the electrochemically active material layer.

Abstract: Provided are examples of electrochemically active electrode materials, electrodes using such materials, and methods of manufacturing such electrodes. Electrochemically active electrode materials may include a high surface area template containing a metal silicide and a layer of high capacity active material deposited over the template. The template may serve as a mechanical support for the active material and/or an electrical conductor between the active material and, for example, a substrate. Due to the high surface area of the template, even a thin layer of the active material can provide sufficient active material loading and corresponding battery capacity. As such, a thickness of the layer may be maintained below the fracture threshold of the active material used and preserve its structural integrity during battery cycling.

Abstract: Provided are examples of electrochemically active electrode materials, electrodes using such materials, and methods of manufacturing such electrodes. Electrochemically active electrode materials may include a high surface area template containing a metal silicide and a layer of high capacity active material deposited over the template. The template may serve as a mechanical support for the active material and/or an electrical conductor between the active material and, for example, a substrate. Due to the high surface area of the template, even a thin layer of the active material can provide sufficient active material loading and corresponding battery capacity. As such, a thickness of the layer may be maintained below the fracture threshold of the active material used and preserve its structural integrity during battery cycling.

Abstract: A lithium ion battery electrode includes silicon nanowires used for insertion of lithium ions and including a conductivity enhancement, the nanowires growth-rooted to the conductive substrate.

Abstract: Provided are novel electrolytes for use in rechargeable lithium ion cells containing high capacity active materials, such as silicon, germanium, tin, and/or aluminum. These novel electrolytes include one or more pyrocarbonates and, in certain embodiments, one or more fluorinated carbonates. For example, dimethyl pyrocarbonate (DMPC) may be combine with mono-fluoroethylene carbonate (FEC). Alternatively, DMPC or other pyrocarbonates may be used without any fluorinated carbonates. A weight ratio of pyrocarbonates may be between about 0% and 50%, for example, about 10%. Pyrocarbonates may be combined with other solvents, such as ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and/or ethyl-methyl carbonate (EMC). Alternatively, pyrocarbonates may be used without such solvents.