Positive electrode active substance, positive electrode, and non-aqueous electrolyte secondary battery

A positive electrode active substance comprising a lithium-containing metal oxide represented by the following general formula (1):

• LiFe1-xMxP1-ySiyO4 (1)
• wherein M represents an element selected from Sn, Zr, Y, and Al;
• 0<x<1;
• and 0<y<1,
• wherein the lithium-containing metal oxide has a lattice constant and a half value width of a diffraction peak of a (011) plane, providing a capacity retaining ratio of higher than 81.0% after 100 times of charging and discharging of a cell having a positive electrode comprising the lithium-containing metal oxide, an electrolyte, and a counterelectrode;
• wherein the positive electrode consists about 10 wt % of acetylene black, about 10 wt % of fluororesin, and about 80 wt % of lithium-containing metal oxide;
• and is 20 mg in weight;
• the electrolyte consists 50 vol % of ethylene carbonate into which 1 mol/liter of LiPF6 is dissolved and 50 vol % of diethyl carbonate, and is 30 ml in volume;
• and
• the counterelectrode consists metal lithium, and
• the cell is charged and discharged 100 times under the following conditions:
• in an environment of 25° C., with a charging and discharging current of 0.1 mA, with an electric potential of 4.0 V at the end of the charge of the cell, and with an electric potential of 2.0 V at the end of the discharge of the cell.