| 摘要 |
PROBLEM TO BE SOLVED: To allow rapid charge/discharge, and improve voltage resistance, capacity, energy density, and cycle reliability, by impregnating an element where a positive electrode is faced to a negative electrode through a separator into an electrolyte, and then charging the element at a specific current density, and storing lithium ions in a carbon material. SOLUTION: A current density when lithium ions are stored in a negative electrode carbon material is 0.01-100 A per 1 g carbon material. Once the lithium ions are stored, the current density is not required to be adjusted during subsequent charge/discharge. Thickness of a negative electrode is 7-70% of thickness of a positive electrode. The thickness of the positive electrode is preferably 80-250 μm. In the carbon material, surface interval of the [002] surface due to X-ray diffraction is preferably 0.335-0.410 nm. Especially, graphite based carbon material is preferable. A solvent of the electrolyte preferably contains at least 70 wt.% propylene carbonate. |
