| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a negative electrode material for a lithium ion secondary battery enabling high density and excellent in electrolyte permeability. <P>SOLUTION: A negative electrode material for a lithium ion secondary battery contains a carbon particle group and is in a volumetric cumulative distribution curve from a small diameter side in a particle diameter distribution of the carbon particle group. When first carbon particles represent carbon particles having a particle diameter of 0.9 to 1.1 times a particle diameter D90 at the point where the cumulative percentage is 90%, and second carbon particles represent carbon particles having a particle diameter of 0.9 to 1.1 times a particle diameter D10 at the point where the cumulative percentage is 10%, the ratio (P<SB POS="POST">D10</SB>/P<SB POS="POST">D90</SB>) of the average fracture strength (P<SB POS="POST">D10</SB>) of the second carbon particles to the average fracture strength (P<SB POS="POST">D90</SB>) of the first carbon particles is in the range of 1.7 to 75. <P>COPYRIGHT: (C)2012,JPO&INPIT |
