NEGATIVE ELECTRODE MATERIAL, NEGATIVE ELECTRODE USING THIS, AND LITHIUM ION BATTERY AND LITHIUM POLYMER BATTERY USING THE NEGATIVE ELECTRODE

摘要

PROBLEM TO BE SOLVED: To provide a negative electrode material and a negative electrode using this in which the insertion and elimination reaction of a lithium ion accompanying charge and discharge progresses smoothly and high rate charge and discharge characteristics are improved. SOLUTION: The negative electrode material contains a first carbon material 11 of a particle shape having an average particle size of 5-40μm and a second carbon material 14 having as a principal component a carbon nanofiber 13 in which a graphite screen 12 of a plane shape having the average diameter of 10-500 nm is laminated in several layers and graphite screens are in substance perpendicular to the longitudinal axis of the fiber, and the nanofiber has a length of 1,000 nm or longer and an aspect ratio of 10 or more, and the ratio of the first carbon material is 98-70 wt% and the ratio of the second carbon material is 2-30 wt%. The second carbon material of the negative electrode material contains powder form coagulum 16 made of carbon fine powder having a graphite structure in addition to the nanofiber, and the nanofiber has a ratio of 80-99.5 wt% and the powder form coagulum has a ratio of 0.5-20 wt%. COPYRIGHT: (C)2004,JPO&NCIPI