Abstract: This invention provides a nonaqueous electrolyte secondary battery including an electrode group comprising a positive electrode, a negative electrode, and a separator for separating the positive and negative electrodes from each other, a jacket for housing the electrode group, and a nonaqueous electrolyte with which the electrode group is impregnated. The separator contains a porous sheet whose air permeability is 600 sec/100 cm3 or less. The positive electrode and the separator are adhered to each other by adhesive polymers that are held in voids of the positive electrode and those of the separator, and the negative electrode and the separator are adhered to each other by adhesive polymers that are held in voids of the negative electrode and those of the separator.

Abstract: This invention provides a lithium secondary battery comprising a positive electrode, and a negative electrode comprising a carbonaceous material which is capable of absorbing or desorbing lithium ion, wherein the carbonaceous material comprises 1 to 10% by weight of boron and 0.1 to 1% by weight of oxygen, and has an intensity ratio (P.sub.101 /P.sub.100) i.e., a ratio in intensity of a (101) diffraction peak P.sub.101 to a (100) diffraction peak P.sub.100 as measured by means of powder X-ray diffraction, of 2 or more.