| 摘要 |
A lithium ion secondary battery having high output characteristics even at an extremely low temperature, for example, -30° C. and high output power even in a low charged state. A graphite-based material having an R value (I<SUB>RD</SUB>/I<SUB>RG</SUB>) which is the ratio of peak intensity (I<SUB>RD</SUB>) at 1,300 to 1,400 cm<SUP>-1 </SUP>to peak intensity (I<SUB>RG</SUB>) at 1,580 to 1,620 cm<SUP>-1 </SUP>measured in its Raman spectrum of 0.3 to 0.6 and an H value (I<SUB>H(110)</SUB>/I<SUB>H(004)</SUB>) which is the ratio of the peak height intensity (I<SUB>H(110)</SUB>) of the face (110) to the peak height intensity (I<SUB>H(004)</SUB>) of the face (004) in its X-ray diffraction of 0.5 to 2.0 or a C value which is the ratio of the peak integral intensity (I<SUB>C(110)</SUB>) of the face (110) to the peak integral intensity (I<SUB>C(004)</SUB>) of the face (004) of 0.4 to 1.50 is used as a negative-electrode active material.
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