Positive electrode layer

A positive electrode layer used in a lithium ion secondary battery,

• wherein the positive electrode layer contains a positive electrode active material and carbon nanotubes,
• wherein the positive electrode active material contains tungsten and is secondary particles including a plurality of primary particles and voids formed between the plurality of primary particles,
• wherein the positive electrode layer contains, as the carbon nanotubes, first carbon nanotubes of which at least some are included in the voids of the secondary particles, and
• wherein spectrums at rising positions (10,195 eV to 10,206 eV) of peaks of L absorption edges of tungsten measured by X-ray absorption fine structure analysis (XAFS) satisfy:
• (
• a
• -
• b
• )
• /
• (
• c
• -
• b
• )
• ≤
• 0
• .
• 7
• ⁢
• 9
• Formula
• ⁢
• (
• 1
• )
• [in Formula (1), a represents an energy (eV) when the slope of the spectrum is the largest in the range of 10,195 eV to 10,206 eV, and
• when a spectral intensity at a (eV) is set as A,
• b represents an energy (eV) at which the spectral intensity becomes A in a range of 10,195 eV to 10,206 eV of WO2 (tungsten(IV) oxide), and
• c represents an energy (eV) at which the spectral intensity becomes A in a range of 10,195 eV to 10,206 eV of WO3 (tungsten(VI) oxide)].