131results about How to "Improve initial efficiency" patented technology

Anode active materials and methods of preparing the same are provided. One anode active material includes a carbonaceous material capable of improving battery cycle characteristics. The carbonaceous material bonds to and coats metal active material particles and fibrous metallic particles to suppress volumetric changes.

A composite anode active material includes a composite of a carbon-based anode active material, a metal-based anode active material and polymer particles. By increasing the conductivity of the composite anode active material, a lithium battery having a large capacity, high initial efficiency, high rate capability and improved cycle life performance can be obtained. An anode includes the composite anode active material and a lithium battery includes the anode.

An negative active material for a rechargeable lithium battery includes a nano-composite including a Si phase, a SiO₂ phase, and a metal oxide phase of formulation M_yO, where M is a metal with an oxidation number x, a free energy of oxygen-bond formation ranging from −900 kJ/mol to −2000 kJ/mol, x, and x·y=2. The negative active material for a rechargeable lithium battery according to the present invention can improve initial capacity, initial efficiency, and cycle-life characteristics by suppressing its initial irreversible reaction.

Negative active materials for rechargeable lithium batteries, methods of manufacturing the negative active materials, and rechargeable lithium batteries including the negative active materials are provided. One negative active material includes an active metal core and a crack inhibiting layer formed on the core. The crack inhibiting layer includes a carbon-based material.

A negative active material for a rechargeable lithium battery with a composite phase particle has a chemical formula, SiO_x, where 0<x<1. The material comprises a first crystalline phase of Si nano-grains, and a second phase of non-crystalline SiO₂, where the composite phase particle has a Si-phase peak of 150 to 480 cm⁻¹ according to Raman spectroscopic analysis.

The present invention is a method for manufacturing a negative electrode active material for a non-aqueous electrolyte secondary battery comprising at least depositing silicon on a substrate by vapor deposition by using a metallic silicon as a raw material, the substrate having a temperature controlled to 300° C. to 800° C. under reduced pressure, and pulverizing and classifying the deposited silicon. As a result, there is provided a method for manufacturing a negative electrode active material composed of silicon particles that is an active material useful as a negative electrode of a non-aqueous electrolyte secondary battery in which high initial efficiency and high battery capacity of silicon are kept, cycle performance is superior, and an amount of a change in volume decreases at the time of charge and discharge.

The present invention provides a negative electrode material for a lithium ion secondary battery, a composite negative electrode material for a lithium ion secondary battery, a resin composition for a lithium ion secondary battery negative electrode, and a negative electrode for a lithium ion secondary electrode, which may provide high charge/discharge capacity, and excellent initial charge-discharge characteristics and capacity retention. The surfaces of core particles of silicon of 5 nm or more and 100 nm or less in average particle size are coated with a coating layer to use a negative electrode material containing substantially no silicon oxide in the coating layer, or a composite negative electrode material for a lithium ion secondary battery, which includes the negative electrode material and a matrix material, further with the use of a polyimide resin or a precursor thereof as a bonding resin, thereby making it possible to achieve high charge/discharge capacity and excellent capacity retention, as well as high initial efficiency.

A surface treated anode and a lithium battery using the same are provided. The surface treated anode includes a current collector, and an anode active material layer formed on the current collector. The anode active material layer is treated with an amine group containing compound.

An anode active material for a lithium rechargeable battery, the anode active material including: a base material which is alloyable with lithium and a metal nitride disposed on the base material.

A positive active material including: a lithium-containing oxide, and a lithium-intercalatable phosphate compound disposed on the lithium-containing oxide.

The invention puts forward a radar track initiation method based on location information and Doppler information in order to solve the technical problem that the existing sequential processing technical method is of low track initiation efficiency. The method is implemented by the steps as follows: calculating the maximum unambiguous velocity; selecting a track head from measurement vectors scanned at the kth time, and calculating a radial velocity set; building a distance constraint accord to the radial velocity; building a space constraint according to the maximum velocity; during (k+1)th scanning, associating measurement vectors which are on the same Doppler channel with the track head and meet the two constraints; using effective measurement vectors to update the distance constraint, and continuing the association operation; building a stable track according to the track initiation criterion; and traversing the measurement vectors scanned at the kth time and a corresponding radial velocity set. The method of the invention is of high track initiation efficiency, and can be used in target tracking.

A negative electrode active material for a non-aqueous electrolyte secondary battery, including negative electrode active material particles containing a silicon compound expressed by SiO_x where 0.5≦x≦1.6, the negative electrode active material particles at least partially coated with a carbon coating, the carbon coating exhibiting a specific surface area ranging from 5 m²/g to 1000 m²/g, the specific surface area being measured by a multipoint BET method after the carbon coating is separated from the negative electrode active material particles, the carbon coating exhibiting a compression resistivity ranging from 1.0×10⁻³ Ω·cm to 1.0 Ω·cm when the carbon coating is compressed so as to have a density of 1.0 g/cm³, the compression resistivity being measured after the carbon coating is separated from the negative electrode active material particles. This negative electrode active material can increase the battery capacity and improve the cycle performance and battery initial efficiency.

The lowness of the initial efficiency which is a drawback of lithium secondary batteries wherein a SiO negative electrode is used is largely made better without hindering a large initial charge capacity peculiar to the lithium secondary batteries. A fall in the cycle characteristic when the thickness of the SiO layer is made large is prevented. To realize these matters, a thin film of SiO is formed, as a negative electrode active material layer, on the surface of a current collector by vacuum evaporation or sputtering. The film is preferably formed by an ion plating process. The thickness of the SiO thin film is set to 5 μm or more. The surface roughness of the current collector is set to follows: the maximum height roughness Rz=5.0 or more. After the formation of the thin film, the film is thermally treated in a nonoxidative atmosphere.

A positive electrode active material including a lithium transition metal oxide, wherein when a lithium battery including a positive electrode including the lithium transition metal oxide is analyzed by differential capacity analysis, an irreversible peak is present in a graph of differential capacity versus voltage in a range of about 4.5 volts versus lithium to about 4.8 volts versus lithium during a first charge/discharge cycle.

An object of the invention is to provide such an additive for a lithium secondary battery that improves the battery capacity and the initial efficiency of the lithium secondary battery. In the invention, a fullerene derivative having a group having a formula weight of 6 or more is used as an additive for a lithium secondary battery. A fullerene derivative having a group having a formula weight of 6 or more is contained in an anode material for a lithium secondary battery, an anode for a lithium secondary battery, and a lithium secondary battery using an anode containing the anode material. The group having a formula weight of 6 or more in the fullerene derivative is preferably one selected from the group consisting of an alkali metal atom, a chalcogen atom, a halogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a heterocyclic group, a characteristic group containing oxygen, a characteristic group containing sulfur and a characteristic group containing nitrogen.

Provided are: an anode active material for a lithium ion secondary battery with which high initial efficiency and battery capacity can be maintained and excellent cycling characteristics are achieved; and a method for producing such an active material. The anode active material for a lithium ion secondary battery, the active material comprising a Si compound and a carbonaceous material or a carbonaceous material and graphite, is obtained by a method comprising the steps of:

• • mixing a Si compound, a carbon precursor, and, as appropriate, graphite powder;
  • performing granulation/compaction;
  • pulverizing the mixture to form composite particles;
  • firing the composite particles in an inert gas atmosphere; and
  • subjecting the pulverized and conglobated composite powder or the fired powder to air classification.

The present invention relates to a silicon-based composite including a silicon oxide which is coated thereon with carbon and bonded therein to lithium. The present invention also relates to a method of producing a silicon-based composite, comprising coating a surface of silicon oxide with carbon, mixing the silicon oxide coated with carbon with lithium oxide, and heat-treating a mixture of the silicon oxide coated with carbon and the lithium oxide in an inert atmosphere.

Provided are a negative electrode active material for a secondary battery, in which a silicon-based negative electrode active material is formed in a three-layer structure including an amorphous matrix, thereby suppressing a dispersal phenomenon of the negative electrode active material during charging/discharging. The negative electrode active material having a three-layer structure includes: a silicon (Si) layer; an amorphous matrix layer outside the Si layer; and a nano grain matrix layer formed on an interface between the Si layer and the amorphous matrix layer.

A negative electrode active material and a secondary battery are provided. The negative electrode active material can be useful in maintaining excellent cell efficiency and lifespan while showing high-capacity properties, and the secondary battery may be manufactured using the negative electrode active material.