140results about How to "Improve initial efficiency" patented technology

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.

The present invention provides a negative electrode active material for a non-aqueous electrolyte secondary cell having negative electrode active material particles, the negative electrode active material particles having a silicon compound (SiOx; where 0.5 <= x <= 1.6) containing a Li compound, wherein the negative electrode active material for a non-aqueous electrolyte secondary cell is characterized in that: the silicon compound has a carbon coating formed at least partially thereon; the negative electrode active material particles include a coating comprising a compound having a boron-fluorine bond and / or a compound having a phosphorus-fluorine bond on at least a part of the surface of the silicon compound, the carbon coating, or both; and the negative electrode active material particles contain elemental boron or elemental phosphorus in a range of 10 mass ppm to 10,000 mass ppm in relation to the total amount of the negative electrode active material particles. A negative electrode active material for a non-aqueous electrolyte secondary cell with which it is possible to increase cell capacity and improve cycle characteristics and initial cell efficiency is thereby provided.

This negative electrode material has a high discharge capacity per unit mass and excellent initial efficiency. By using the negative electrode material, it is possible to provide a high-capacity lithium-ion battery with excellent charge-discharge cycle characteristics. The present invention pertains to a negative electrode material for lithium-ion batteries that includes silicon-containing particles, artificial graphite particles, and a carbonaceous material. At least a portion of the silicon-containing particles, artificial graphite particles, and carbonaceous material are combined together into composite particles. The silicon-containing particles have a SiOx layer (0 < x <= 2) on the particle surface and an oxygen content of 1.0 mass% to 18.0 mass% inclusive, with particles having a primary particle diameter of 200 nm or smaller as the main component thereof. The artificial graphite particles are non-scale-shaped particles and have a D50 particle diameter of 1.0 mum to 15.0 mum inclusive, D50 being the particle diameter at 50% of a volume-based cumulative size distribution measured by laser diffractometry. The present invention also pertains to a lithium-ion battery provided with a negative electrode using the negative electrode material.

Provided are: a negative electrode active material for a lithium ion secondary battery with which high initial efficiency and battery capacity can be maintained and excellent cycling characteristics achieved; and a method for producing said active material. This negative electrode active material for a lithium ion secondary battery, said active material comprising an Si compound, and a carbon substance or a carbon substance and graphite, is obtained by means of: a step of mixing an Si compound, a carbon precursor, and, in accordance with requirements, a graphite powder; a step of granulation / compaction; a step of pulverizing the mixture to form composite particles; a step of firing the composite particles in an inert gas atmosphere; and a step of subjecting the pulverized and spheroidized composite powder or the fired powder to air classification.

The present invention relates to a method for manufacturing a negative electrode, the method comprising the steps of: immersing a preliminary negative electrode in a pre-lithiation solution containingan organic lithium compound and a pre-lithiation solvent; and taking the preliminary negative electrode out of the pre-lithiation solution, and then removing the pre-lithiation solvent present on thepreliminary negative electrode, wherein the preliminary negative electrode comprises a current collector and a preliminary negative electrode active material layer disposed on the current collector,the preliminary negative electrode active material layer containing a negative electrode active material, and the standard reduction potential of the organic lithium compound is lower than the standard reduction potential of the negative electrode active material.

The present invention provides a carbon material which enables the achievement of a nonaqueous secondary battery that has high capacity, high initial efficiency and low charge resistance, while exhibiting excellent productivity. Consequently, the present invention stably and efficiently provides a high-performance nonaqueous secondary battery. A composite carbon material for nonaqueous secondary batteries, which contains at least (A) bulk mesophase artificial graphite particles and (B) graphite particles having an aspect ratio of 5 or more, and which is capable of absorbing and desorbing lithium ions. This composite carbon material for nonaqueous secondary batteries is characterized in that: on a part of the surface of each bulk mesophase artificial graphite particle (A), the graphite crystal lamellar structures of the graphite particles (B) are aligned in the same direction as the outer circumferential surface of the bulk mesophase artificial graphite particle (A); and the average circularity thereof is 0.9 or more.