NEGATIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION SECONDARY BATTERY, NEGATIVE ELECTRODE FOR LITHIUM ION SECONDARY BATTERY INCLUDING THE SAME, AND LITHIUM ION SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide: a negative electrode active material for a lithium ion secondary battery, suppressing deterioration due to the expansion and contraction of a negative electrode active material caused by absorbing and desorbing Li and capable of achieving a lithium ion secondary battery having excellent cycle characteristics; a negative electrode for a lithium ion secondary battery including the negative electrode active material; and a lithium ion secondary battery.SOLUTION: A negative electrode active material for a lithium ion secondary battery includes a core particle capable of repeatedly absorbing and desorbing lithium and a conductive coating film on the surface of the core particle. The compressive strength of the conductive coating film is relatively high on a side closer to the surface of the core particle, and is lower at least at a part on a side far from the surface of the core particle than that on the side closer to the surface of the core particle.