| 摘要 |
PROBLEM TO BE SOLVED: To provide a lithium secondary battery having an excellent life characteristic such as a cycle characteristic and a storage characteristic. SOLUTION: This lithium secondary battery has a positive electrode active material formed of an LiNiO2 compound expressed by a formula LixNi1-yMyO2 (M is at least one kind of element selected from a group of B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Cu, Al, In, Nb, Mo, W, Y and Rh. 0.05<=x<=1.1, 0<=y<=0.5), and a negative electrode active material comprising a core formed of a graphite material having crystal structure, and a surface layer part formed of a carbonaceous material of turbostratic structure formed on the surface of the core. The negative electrode active material has such characteristics that the average lattice spacing d (002) measured by an X-ray powder analysis is 0.340 nm or less and that the R-value of a peak intensity ratio of 1360 cm-1 to 1580 cm-1 by argon laser-Raman spectrometry is 0.30-0.55. In the lithium secondary battery, the resistance increase rate is suppressed, and initial capacity and a discharge capacity ratio are held high to show an effect of improving the life characteristic. |
