Negative electrode material for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery using same

Abstract

To provide a mixed carbon material used for an electrode of a nonaqueous secondary battery with excellent characteristics satisfying both rapid charge-discharge characteristics and high cycle characteristics. A negative electrode material for nonaqueous electrolyte secondary battery, comprising the following carbon material A and carbon material B: (Carbon material A) a multilayer-structure carbon material containing a graphitic particle and an amorphous carbon covering the surface of the graphitic particle, which is a carbon material where the interplanar spacing (d002) of 002 planes by the wide-angle X-ray diffraction method is 3.37 Å or less, Lc is 900 Å or more, the tap density is 0.8 g / cm 3 or more, and the Raman R value that is a ratio of the peak intensity near 1,360 cm -1 to the peak intensity near 1,580 cm -1 in the argon ion laser Raman spectrum, is from 0.25 to 0.6, (Carbon material B) a graphitic particle where the interplanar spacing (d002) of 002 planes by the wide-angle X-ray diffraction method is 3.37 Å or less, Lc is 900 Å or more, the tap density is 0.8 g / cm 3 or more, the Raman R value that is a ratio of the peak intensity near 1,360 cm -1 to the peak intensity near 1,580 cm -1 in the argon ion laser Raman spectrum, is from 0.2 to 0.5, and the average degree of circularity as determined by a flaw-type particle analyzer is 0.9 or more.

Description

technical field [0001] The present invention relates to a carbon material for a negative electrode of a non-aqueous electrolyte secondary battery. In addition, the present invention also relates to a negative electrode for a nonaqueous electrolyte secondary battery using the carbon material for a negative electrode, and a nonaqueous electrolyte secondary battery including the negative electrode. Background technique [0002] A nonaqueous lithium secondary battery including a positive electrode and a negative electrode capable of occluding and releasing lithium ions, and a nonaqueous electrolyte in which lithium salts such as LiPF6 and LiBF4 are dissolved has been developed and put into practical use. [0003] As the negative electrode material of this battery, various schemes have been proposed, but from the viewpoints of high capacity and excellent flatness of discharge voltage, artificial graphite obtained by graphitization of natural graphite, coke, etc., graphitized grap...

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Problems solved by technology

[0007] In order to improve cycle characteristics, for example, Patent Document 2 proposes a non-aqueous lithium secondary battery obtained by using the following carbonaceous particles and the following amorphous carbonaceous particles as negative electrode materials, wherein the carbonaceous particles have multiple layer structure, and the R value obtained by Raman spectroscopy is above 0.2; the crystallinity of the amorphous carbonaceous particles is low, and the X-ray interplanar distance d002 is However, this non-aqueous lithium secondary battery has the problem of an increase in irreversible capacity due to amorphous carbon particles, and further improvement in the cycle characteristics and rapid charge-discharge characteristics required for recent lithium secondary batteries is required.

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