The lithium ion secondary battery

Provided that decrease the battery capacity is low and a high energy density lithium ion secondary batteries in the rapid charging process. In the lithium ion secondary battery, positive electrode comprising the formula (I) represented by and having a 0.2 m2 / g specific surface area of ​​~ 1 m2 / g of lithium nickel manganese oxide: LixNiaM1bMn2-a-bO4 (I ) (in the formula (I) wherein, M1 represents at least one selected from Ti, Si, Co, Fe, Cr, Al, Mg, B and Li; 0 & lt; x≤1; 0.4≤a≤0.6; and 0 ≤b≤0.4); and a negative electrode comprising the formula (II) represented by and having a 4 m2 / g to 20 m / g specific surface area of ​​the lithium titanium oxide: LiyTi5 / 3-cM2cO4 (II) (in in formula (II), M2 represents a group selected Ta, Zr, Cr, at least one of Ni and V; 4 / 3≤y≤7 / 3 and 0≤c & lt; 0.1).