| abstract |
A secondary cell having a high energy density and improved charging/discharging characteristics is disclosed. A stack of a positive electrode (13), a negative electrode (15), and a separator (16) between the electrodes are accommodated in a can (11) which is filled with an electrolytic solution (17). The negative electrode (15) contains a negative electrode material that can occlude/release lithium ions, and metallic lithium is deposited on the negative electrode (15) when the open circuit voltage is lower than the overcharge voltage. Namely, in the initial period of charging, lithium ions are absorbed in the negative electrode material, and from a point of time during charging, metallic lithium is deposited on the negative electrode material. The deposition capacity of metallic lithium is preferably 0.05 to 3.0 times of the charge capacity of the negative electrode material. Thereby, high energy density and satisfactory cycle characteristics are achieved. |