LOW CRYSTALLINITY VANADIUM SULFIDE

Provided is an electrode active material for lithium-ion secondary batteries exhibiting excellent capacity. Specifically, provided is a low-crystalline vanadium sulfide comprising vanadium and sulfur as constituent elements, wherein the composition ratio of the sulfur to the vanadium (S/V) is 3.5 or more in terms of the molar ratio, the average particle size D50 is 10 μm or less, and the low-crystalline vanadium sulfide has no peak at 2θ=53.0° with a tolerance of ±1.0° in an X-ray diffractogram obtained using Cu Kα radiation.