Positive electrode active substance for all solid-state lithium secondary battery

A positive electrode active substance for an all solid-state lithium secondary battery,

• wherein a surface of present core particles composed of a lithium metal composite oxide having a layered structure containing Li, M element, where M comprises at least one element or a combination of two or more elements selected from the group consisting of Ni, Co, Mn, and Al, and O is coated with an amorphous compound containing Li, A, where A represents one element or a combination of two or more elements selected from the group consisting of Ti, Zr, Ta, Nb, Zn, W, and Al, and O;
• wherein, with regard to a D50, a mode diameter, and a D10 according to a measurement of a volume-based particle size distribution obtained via measurements by a laser diffraction scattering-type particle size distribution measurement method, the D50 is 0.5 to 11 μm, a percentage of a ratio of the absolute value of the difference between the mode diameter and the D50 relative to the mode diameter, (|mode diameter−D50|/mode diameter)×100, is 0 to 25%, a percentage of a ratio of the absolute value of the difference between the mode diameter and the D10 relative to the mode diameter (|mode diameter−D50|/mode diameter)×100, is 20 to 58%;
• and
• wherein a ratio, average primary particle, diameter/D50, of an average primary particle diameter of the positive electrode active substance, which is calculated from a scanning-type electron microscope (SEM) image obtained by a scanning-type electron microscope (SEM), relative to the D50 is 0.01 to 0.99.