| abstract |
Provided is a lithium ion secondary battery which is improved particularly in a low-temperature characteristic. The lithium ion secondary battery disclosed herein includes a ternary positive electrode active material formed of a lithium transition metal composite oxide having at least Ni, Co, and Mn, and a carbon-black-adhered carbon-based negative electrode active material which is formed of a carbon material having a graphite structure in at least part thereof and which has carbon black (CB) that has adhered to at least part of a surface portion. A molar ratio x of Ni calculated by taking a total molar amount of Ni, Co, and Mn in the ternary positive electrode active material as 100 satisfies the condition of 34≦x≦46, and a mass ratio a of carbon black calculated by taking a total mass of the carbon material and carbon black in the carbon-black-adhered carbon-based negative electrode active material as 100 satisfies the condition of 0.3≦α≦5. |