NEGATIVE-ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION CAPACITOR

摘要

[Problem] To reduce the thickness of a negative-electrode active material layer while maintaining the conventional level of energy density. [Solution] This negative-electrode active material for a lithium ion capacitor is a composite carbon material formed from carbon black and a carbonaceous material, wherein carbon black having an average particle size of 12 to 300 nm according to electron microscopy is mixed with a carbon precursor such as pitch, the resulting mixture is carbonized or graphitized by baking at 800°C to 3200°C, and then pulverized such that the average particle size (D50) thereof is 1 to 20 μm and the BET specific surface area is between 100 m2/g to 350 m2/g inclusive. An initial charging capacity of at least 700 mAh/g can be achieved, and the cell volume can be reduced because the thickness of the negative-electrode active material layer can be reduced.