Patent ID: 8785047

Claim:
A lithium-ion secondary battery comprising: a positive electrode collector having a surface formed with a positive electrode active material layer containing a positive electrode active material; a negative electrode collector having a surface formed with a negative electrode active material layer containing a negative electrode active material; an electrically insulating porous separator; and an electrolyte containing a lithium salt and being in contact with the positive electrode active material layer, the negative electrode active material layer, and the separator; wherein the positive and negative electrode collectors are disposed such that the positive and negative electrode active material layers hold the separator therebetween; wherein the negative electrode active material is a carbon material having a graphite structure; wherein the amount of the carbon material supported by the negative electrode active material layer is 2.2 to 4.0 mg/cm 2 ; and wherein the graphite structure in an X-ray diffraction pattern of the carbon material exhibits a peak intensity P101 of (101) plane and a peak intensity P100 of (100) plane having a ratio (P101/P100) of 2.4 to 2.8 therebetween.