Carbon materials for lithium-ion secondary batteries

A secondary battery, lithium ion technology, applied in secondary batteries, battery electrodes, circuits, etc., can solve the problem of irreversible capacity increase, and achieve the effects of excellent high temperature storage characteristics, less gas generation, and high capacity

Active Publication Date: 2014-10-15
MITSUBISHI RAYON CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, Patent Document 2 does not describe the increase in irreversible capacity due to the reaction between the acidic functional group and the electrolyte solution at the time of initial charging and the improvement of gas generation, which are problems when introducing an acidic functional group on the surface of the carbon material.

Method used

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  • Carbon materials for lithium-ion secondary batteries

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0183] With the spherical natural graphite that measures in the above-mentioned measuring method, surface functional group amount O / C value is 2.90% in the mixed acid solution of concentrated hydrochloric acid (33wt%) and concentrated nitric acid (40wt%) (concentrated hydrochloric acid: concentrated nitric acid (weight ratio) =1:1) at 80°C for 4 hours, washed with pure water until the pH became 4 or more, and filtered. Furthermore, the sample obtained here was stirred in concentrated sulfuric acid (93 wt%) at 80° C. for 4 hours, washed with pure water until the pH became 4 or higher, and then kept at 300° C. for 6 hours to obtain a sample. Measure particle size d50, tap density, BET specific surface area (SA), Raman R value, surface functional group amount O / C value, surface functional group amount S 165 / C value, Cl / C value of surface functional groups, 3R / 2H, fluidity index a, expansion of laminated battery during 24-hour high-temperature endurance test at 85°C (referred to ...

Embodiment 2

[0185] The spherical natural graphite measured in the above-mentioned measuring method, the surface functional group amount O / C value is 3.04% in the mixed acid solution of concentrated hydrochloric acid and concentrated nitric acid (concentrated hydrochloric acid: concentrated nitric acid (weight ratio)=1: 1) at 80 The mixture was stirred for 8 hours at °C, washed with pure water until the pH became 4 or more, and filtered. Furthermore, the sample obtained here was stirred in concentrated sulfuric acid at 80° C. for 4 hours, washed with pure water until the pH became 4 or higher, and then kept at 300° C. for 6 hours to obtain a sample. The same measurement as in Example 1 was performed on this. The results are shown in Table 1.

Embodiment 3

[0187] The spherical natural graphite measured in the above-mentioned measuring method, the surface functional group amount O / C value is 3.66% in the mixed acid solution (concentrated hydrochloric acid: concentrated nitric acid (weight ratio)=1: 1) of concentrated hydrochloric acid and concentrated nitric acid at 80 °C for 2 hours, washed with pure water until the pH became 4 or more, and filtered. Furthermore, the sample obtained here was stirred in concentrated sulfuric acid at 80° C. for 2 hours, washed with pure water until the pH became 4 or higher, and then kept at 300° C. for 6 hours to obtain a sample. The same measurement as in Example 1 was performed on this. The results are shown in Table 1.

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Abstract

The invention provides a negative electrode material capable of obtaining a lithium-ion secondary battery with sufficiently small charge-discharge irreversible capacity during initial cycle, excellent high-temperature storage characteristics, and reduced gas generation during initial cycle and high-temperature storage. A carbon material for a lithium ion secondary battery, characterized in that the O / C value of the surface functional group represented by the following formula 1 is 1% to 4%, and the Cl / C value of the surface functional group represented by the following formula 2 is the same as The sum of the surface functional group amounts S165 / C (Cl / C+S165 / C) represented by the following formula 3 is 0.05% to 0.5%. Formula 1: O / C value (%) = O atom concentration calculated based on the peak area of ​​the O1s spectrum in X-ray photoelectron spectroscopy (XPS) analysis / C atoms calculated based on the peak area of ​​the C1s spectrum in XPS analysis Concentration × 100; Formula 2: Cl / C value (%) = Cl atomic concentration obtained based on the peak area of ​​the Cl2p spectrum in XPS analysis / C atomic concentration obtained based on the peak area of ​​the C1s spectrum in XPS analysis × 100 Formula 3: S165 / C value (%)=based on the S165 atomic concentration obtained based on the peak area of ​​the peak near 165eV in the spectrum corresponding to S2p in the XPS analysis / based on the peak area of ​​the C1s spectrum in the XPS analysis. C atomic concentration × 100.

Description

technical field [0001] The present invention relates to a carbon material used in a lithium ion secondary battery, a negative electrode for a lithium ion secondary battery formed using the material, and a lithium ion secondary battery having the negative electrode. Background technique [0002] In recent years, demand for high-capacity secondary batteries is increasing along with miniaturization of electronic equipment. In particular, lithium-ion secondary batteries, which have higher energy density and better high-current charge-discharge characteristics than nickel-cadmium batteries and nickel-hydrogen batteries, have attracted attention. In the past, increasing the capacity of lithium-ion secondary batteries has been extensively studied, but in recent years, the demand for high-performance lithium-ion secondary batteries has also increased, and a further increase in capacity is required. [0003] As negative electrode materials for these lithium ion secondary batteries, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/587
CPCY02E60/122H01M4/1393H01M10/0525H01M4/133H01M4/587C01P2002/82C01P2004/51C01P2006/11C01P2006/12C01P2006/20C01B32/05C01B32/21Y02E60/10C01P2006/40C01P2002/70
Inventor 山田俊介山口庆太野濑太助佐藤秀治
Owner MITSUBISHI RAYON CO LTD
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