Non-aqueous electrolyte secondary battery and method of manufacturing the same

A non-aqueous electrolyte secondary battery comprising:

• a negative electrode, a non-aqueous electrolyte comprising a carbonate-based solvent containing a lithium salt, and a positive electrode having a positive electrode active material comprising sodium oxide, characterized in that:
• the sodium oxide contains lithium;
• the sodium oxide has a main peak at 2θ=17.5° to 19.0° and sub-peaks at 35.5° to 37.5° and 66.0° to 67.5°, as determined by X-ray powder crystal diffraction (Cukα) measured at the time when the battery is charged to 25% to 50% of the battery capacity after manufacture of the battery;
• and the sodium oxide is represented by the general formula NaaLibMnyCozO2±α where 0<a≦0.7, 0<b<1.0, 0.6≦a+b≦1.1, 0.45≦y≦0.55, 0.45≦z≦0.55, 0.90≦y+z≦1.10, and 0≦α≦0.1.

A method of manufacturing a non-aqueous electrolyte secondary battery, comprising the steps of:

• preparing a positive electrode active material comprising a lithium-containing sodium oxide in which the molar amount of lithium is less than the molar amount of sodium by sintering a material containing at least a sodium compound and a lithium compound;
• immersing the positive electrode active material in a non-aqueous electrolyte comprising a carbonate-based solvent containing a lithium salt to ion-exchange the sodium oxide;
• preparing a positive electrode active material slurry containing the positive electrode active material and a binder, and thereafter applying the positive electrode active material slurry to a positive electrode current collector, to prepare a positive electrode;
• interposing a separator between the negative electrode and the positive electrode to prepare a power-generating element;
• and
• enclosing the power generating element into a battery case, and filling an electrolyte solution into the battery case.

A method of manufacturing a non-aqueous electrolyte secondary battery, comprising the steps of:

• preparing a positive electrode active material comprising a lithium-containing sodium oxide in which the molar amount of lithium is less than the molar amount of sodium by sintering a material containing at least a sodium compound and a lithium compound;
• preparing a positive electrode active material slurry containing the positive electrode active material and a binder, and thereafter applying the positive electrode active material slurry to a positive electrode current collector, to prepare a positive electrode;
• immersing the positive electrode in a non-aqueous electrolyte comprising a carbonate-based solvent containing a lithium salt to ion-exchange the sodium oxide;
• interposing a separator between the negative electrode and the positive electrode to prepare a power-generating element;
• and
• enclosing the power generating element into a battery case, and filling an electrolyte solution into the battery case.

A method of manufacturing a non-aqueous electrolyte secondary battery, comprising the steps of:

• preparing a positive electrode active material comprising a lithium-containing sodium oxide having a main peak at 2θ=15.9° to 16.9° as determined by X-ray powder crystal diffraction (Cukα) and in which the molar amount of lithium is less than the molar amount of sodium, by sintering a material containing at least a sodium compound and a lithium compound;
• preparing a positive electrode active material slurry containing the positive electrode active material and a binder, and thereafter applying the positive electrode active material slurry to a positive electrode current collector, to prepare a positive electrode;
• interposing a separator between the negative electrode and the positive electrode to prepare a power-generating element;
• and
• enclosing the power generating element into a battery case, and filling a non-aqueous electrolyte comprising a carbonate-based solvent containing a lithium salt into the battery case to ion-exchange the sodium oxide.