Abstract: A lithium-ion secondary battery includes a negative electrode having a negative electrode mixture layer containing a negative electrode active material and a separator. The negative electrode active material contains a carbon material having an R value of Raman spectrum of 0.2 to 0.8 and having an interplanar spacing d002 between 002 lattice planes of 0.340 nm or less, a ratio of the carbon material is 60 mass % or more based on the total amount of the negative electrode active material, a density of the negative electrode mixture layer is 1.40 g/cm3 to 1.65 g/cm3, and the separator is formed from a laminate composed of a porous layer containing resin having a melting point of 120° C. to 140° C., and a porous layer containing resin having a melting point of 150° C. or higher or a porous layer composed mainly of inorganic particles having a heat resistant temperature of 150° C. or higher.

Abstract: A lithium ion secondary cell comprising a positive electrode, a negative electrode and a non-aqueous electrolytic solution wherein the negative electrode comprises a negative electrode active material containing a carbonaceous material having a spacing d002 of 0.3360 nm or less, a crystal size Lc in the c-axis direction of at least 70 nm and a R value of from 0.01 to 0.3 where a R value is a ratio of I1350 to I1580 in which I1350 and I1580 are Raman intensities around 1350 cm?1 and 1580 cm?1 in a Raman spectrum, and wherein the non-aqueous electrolytic solution contains 0.5 to 5% by weight of vinylene carbonate or its derivative.

Abstract: A lithium secondary battery includes a positive electrode, a negative electrode and nonaqueous electrolyte, wherein the negative electrode includes a negative active material and a binder, the negative active material comprises graphite A and graphite B, shapes of primary particles of the graphite A are spherical or elliptical, an average particle diameter of the primary particles of the graphite A ranges between 10 ?m and 30 ?m inclusive, sizes of crystallites of the graphite A in a direction of a c-axis are smaller than 100 nm and tap density of the graphite A is 1.0 g/cm3 or higher, shapes of primary particles of the graphite B are flat, an average particle diameter of the primary particles of the graphite B ranges between 1 ?m and 10 ?m inclusive, and sizes of crystallites of the graphite B in a direction of a c-axis are 100 nm or larger, which has a large capacity and excellent cycle characteristics.

Abstract: A lithium ion secondary cell comprising a positive electrode, a negative electrode and a non-aqueous electrolytic solution wherein the negative electrode comprises a negative electrode active material containing a carbonaceous material having a spacing d002 of 0.3360 nm or less, a crystal size Lc in the c-axis direction of at least 70 nm and a R value of from 0.01 to 0.3 where a R value is a ratio of I1350 to I1580 in which I1350 and I1580 are Raman intensities around 1350 cm?1 and 1580 cm?1 in a Raman spectrum, and wherein the non-aqueous electrolytic solution contains 0.5 to 5% by weight of vinylene carbonate or its derivative.