Nonaqueous electrolyte secondary battery

A nonaqueous electrolyte secondary battery, comprising:

• a case having a wall thickness not larger than 0.3 mm;
• a positive electrode provided in said case;
• a negative electrode provided in said case and containing a carbonaceous material capable of absorbing-desorbing lithium ions;
• and
• a nonaqueous electrolyte provided in said case and containing a nonaqueous solvent including γ-butyrolactone and a solute dissolved in said nonaqueous solvent;
• wherein formula (1) given below is satisfied:
• C20≦0.98×C60 (1)
• where C20 represents a negative electrode capacity obtained when said negative electrode of said secondary battery at the time of starting its use is charged to 0.01V versus Li with a current of 0.2C at 20° C., followed by discharging the negative electrode to 1.5V versus Li with a current of 0.2C at 20° C., and C60 represents a negative electrode capacity obtained when said negative electrode of said secondary battery at the time of starting its use is charged to 0.01V versus Li with a current of 0.2C at 60° C., followed by discharging the negative electrode to 1.5V versus Li with a current of 0.2C at 60° C.

A nonaqueous electrolyte secondary battery, comprising:

• a case having a wall thickness not larger than 0.3 mm;
• a positive electrode provided in said case;
• a negative electrode provided in said case and containing a carbonaceous material capable of absorbing-desorbing lithium ions;
• and
• a nonaqueous electrolyte provided in said case and containing a nonaqueous solvent including γ-butyrolactone and a solute dissolved in said nonaqueous solvent;
• wherein a shift value of a peak derived from lithium absorbed in said carbonaceous material of said negative electrode under the state that the secondary battery is fully charged to 4.2V is detected in −1 to 20 ppm and 40 to 50 ppm in the solid state 7Li-NMR using a magic angle spinning method (MAS method).

A nonaqueous electrolyte secondary battery, comprising:

• a case having a wall thickness not larger than 0.3 mm;
• a positive electrode provided in said case;
• a negative electrode provided in said case and containing a carbonaceous material capable of absorbing-desorbing lithium ions;
• and
• a nonaqueous electrolyte provided in said case and containing a nonaqueous solvent including γ-butyrolactone and a solute dissolved in said nonaqueous solvent;
• wherein said carbonaceous material contains at least 90 parts by weight of carbonaceous material A having an average layer spacing d002 derived from (002) reflection, which is obtained by a powder X-ray diffraction, of 0.337 nm or less and 1 to 10 parts by weight of carbonaceous material B having an average layer spacing d002 derived from (002) reflection, which is obtained by a powder X-ray diffraction, of 0.36 to 0.4 nm.

A nonaqueous electrolyte secondary battery, comprising:

• a case having a wall thickness not larger than 0.3 mm;
• a positive electrode provided in said case;
• a negative electrode provided in said case and containing a carbonaceous material capable of absorbing-desorbing lithium ions;
• and
• a nonaqueous electrolyte provided in said case and containing a nonaqueous solvent including γ-butyrolactone and a solute dissolved in said nonaqueous solvent;
• wherein said carbonaceous material contains at least 90 parts by weight of a carbonaceous material obtained by subjecting a carbonaceous material precursor to a heat treatment at 2,500° C. or more and 1 to 10 parts by weight of a carbonaceous material obtained by subjecting a carbonaceous material precursor to a heat treatment at 900° C. or less.

A nonaqueous electrolyte secondary battery, comprising:

• a case having a wall thickness not larger than 0.3 mm;
• a positive electrode provided in said case;
• a negative electrode provided in said case and containing a carbonaceous material capable of absorbing-desorbing lithium ions;
• and
• a nonaqueous electrolyte provided in said case and containing a nonaqueous solvent including γ-butyrolactone and a solute dissolved in said nonaqueous solvent;
• wherein a lithium remaining amount in said negative electrode under the state that the secondary battery is discharged to 3V under a current of 0.2C at room temperature falls within a range of between 1.1% by weight and 2% by weight based on said carbonaceous material.

A nonaqueous electrolyte secondary battery, comprising:

• a case having a wall thickness not larger than 0.3 mm;
• a positive electrode provided in said case;
• a negative electrode provided in said case and containing a carbonaceous material capable of absorbing-desorbing lithium ions;
• and
• a nonaqueous electrolyte provided in said case and containing a nonaqueous solvent including γ-butyrolactone and a solute dissolved in said nonaqueous solvent;
• wherein lithium absorbed in said carbonaceous material of said negative electrode under the state that the secondary battery is discharged to 3V under a current of 0.2C at room temperature exhibits a half-width of a main peak being 70 ppm (10,000 Hz) or less in the solid state 7Li-NMR spectrum measured by a magic angle spinning method (MAS method).