Carbonaceous material for negative electrode of nonaqueous-electrolyte secondary battery, process for producing same, and negative electrode and nonaqueous-electrolyte secondary battery obtained using said carbonaceous material

Abstract

The purpose of the present invention is to provide: a carbonaceous material for the negative electrode of a nonaqueous-electrolyte secondary battery, the carbonaceous material being obtained from a plant-derived organic substance as a starting material, having been sufficiently deashed by removing alkali metals such as potassium element therefrom to have a high purity, and bringing about excellent high-temperature cycle characteristics; and a lithium-ion secondary battery obtained using the carbonaceous material. The carbonaceous material for the negative electrode of a nonaqueous-electrolyte secondary battery is a carbonaceous material obtained by carbonizing a plant-derived organic substance, and has a hydrogen / carbon atomic ratio (H / C), determined by elemental analysis, of 0.1 or less, an average particle diameter (Dv50) of 2-50 µm, an average interplanar spacing of (002) plane, determined by the X-ray diffraction method, of 0.365-0.400 nm, a potassium element content of 0.5 mass% or less, a calcium element content of 0.02 mass% or less, and a true density, determined by the pycnometer method using butanol, of 1.44 g / cm3 or higher but less than 1.54 g / cm3.

Description

Technical field [0001] The invention relates to a carbonaceous material for a non-aqueous electrolyte secondary battery negative electrode subjected to a peroxide treatment and a manufacturing method thereof. Background technique [0002] In recent years, people have paid more and more attention to environmental issues. Therefore, the industry is studying electric vehicles with large-scale lithium ion secondary batteries with high energy density and excellent output characteristics. When used in small portable devices such as mobile phones and notebook computers, the capacity per unit volume becomes particularly important. Therefore, graphite materials with higher density have been mainly used as negative electrode active materials. However, when using lithium ion secondary batteries for vehicles, they are difficult to replace midway due to their large size and high price. Therefore, it is required to have at least the same durability as a car, and to be able to achieve a life p...

AI Technical Summary

Problems solved by technology

For this reason, since the doping and dedoping of lithium will expand and shrink the crystal, structural damage is likely to occur, so the cycle characteristics are low.

Therefore, when the operating temperature is high, the mobility of lithium in the electrolyte will also increase, and lithium doping and dedoping are more likely to occur, and structural damage will be accelerated, resulting in a significant decrease in high-temperature cycle characteristics.

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