| 摘要 |
PROBLEM TO BE SOLVED: To increase discharge capacity and heighten charging and discharging cycle property by providing a positive electrode, containing a compounded oxide containing sodium and iron as the positive electrode active material, a negative electrode containing a carbon material as a sodium ion and lithium ion-storing material, and a nonaqueous electrolytic substance containing lithium ion. SOLUTION: When this battery is charged, sodium ion is isolated from a positive electrode active material and inserted together with lithium in a nonaqueous electrolytic substance into a carbon material of a negative electrode. On the other hand, when the battery is discharged, sodium ion is isolated from the carbon material and inserted into the positive electrode active material, and at the same time lithium ion is isolated from the carbon material and is returned to the nonaqueous electrolytic substance. In this case, since the carbon material is used for the negative electrode, good charging-discharging cycle characteristic is provided. Moreover, since a large quantity of sodium ion is inserted into the carbon material of the negative electrode by inserting sodium ion together with lithium ion in the nonaqueous electrolytic substance into the carbon material of the negative electrode at the time of charging, the discharge capacity is made large. |
