ELECTRODE, SECONDARY BATTERY, BATTERY PACK, ELECTRIC VEHICLE, ELECTRIC POWER STORAGE SYSTEM, ELECTRIC POWER TOOL, AND ELECTRONIC APPARATUS

摘要

A secondary battery includes: a cathode; an anode; and a non-aqueous electrolytic solution, wherein the cathode includes a second lithium-containing compound having an olivine-type crystal structure, a photoelectron spectrum of oxygen 1s obtained by surface analysis of the cathode with the use of X-ray photoelectron spectroscopy includes a third peak and a fourth peak, the third peak having an apex in a range in which binding energy is equal to or larger than 530 electron volts and less than 533 electron volts, and the fourth peak having an apex in a range in which binding energy is from 533 electron volts to 536 electron volts both inclusive and having spectrum intensity smaller than spectrum intensity of the third peak, and a ratio IE/ID between a spectrum intensity ID of the third peak and a spectrum intensity IE of the fourth peak is larger than ¼.

主权项

1. A secondary battery comprising:
a cathode; an anode; and a non-aqueous electrolytic solution, wherein the cathode includes any one of a first lithium-containing compound and a second lithium-containing compound, the first lithium-containing compound having a bedded salt-type crystal structure,
the first lithium-containing compound includes one or more metal elements (M) other than lithium (Li),a photoelectron spectrum of oxygen 1s associated with the first-lithium containing compound and having a horizontal axis representative of binding energy in electron volt and a vertical axis representative of spectrum intensity, the photoelectron spectrum of oxygen 1s obtained by surface analysis of the cathode with the use of X-ray photoelectron spectroscopy includes a first peak and a second peak, the first peak having an apex in a range in which binding energy is from 531 electron volts to 535 electron volts both inclusive, and the second peak having an apex in a range in which binding energy is equal to or larger than 529 electron volts and less than 531 electron volts and having spectrum intensity smaller than spectrum intensity of the first peak,when an atomic ratio (Co/M) of cobalt in the metal element is equal to or larger than 0.5, a ratio IB/IA between a spectrum intensity IA of the second peak and a spectrum intensity IB in the case where binding energy is 535 electron volts is larger than 1, andwhen the atomic ratio (Co/M) of cobalt in the metal element is less than 0.5, a ratio IC/IA between the spectrum intensity IA of the second peak and a spectrum intensity IC in the case where binding energy is 536 electron volts is larger than 1, wherein the second lithium-containing compound having an olivine-type crystal structure,
a photoelectron spectrum of oxygen 1s associated with the second lithium-containing compound and having a horizontal axis representative of a binding energy in electron volt and a vertical axis representative of a spectrum intensity, the photoelectron spectrum of oxygen 1s obtained by surface analysis of the cathode with the use of X-ray photoelectron spectroscopy includes a third peak and a fourth peak, the third peak having an apex in a range in which binding energy is equal to or larger than 530 electron volts and less than 533 electron volts, and the fourth peak having an apex in a range in which binding energy is from 533 electron volts to 536 electron volts both inclusive and having spectrum intensity smaller than spectrum intensity of the third peak, anda ratio IE/ID between a spectrum intensity ID of the third peak and a spectrum intensity IE of the fourth peak is larger than ¼.