| abstract |
a silicon oxide composite comprising i) Si, ii) a silicon oxide represented by SiO x (0 <x ≦ 2), and iii) a magnesium silicate containing Si and Mg; And Located on the surface of the silicon oxide composite, provided with a carbon coating layer containing a carbon-based material, In the X-ray diffraction analysis, peaks by Mg 2 SiO 4 and MgSiO 3 are simultaneously shown, and peaks by MgO are not observed. Had a ratio I (Mg 2 SiO 4) / I (MgSiO 3) of the peak intensity I (Mg 2 SiO 4) and the peak intensity I (MgSiO 3) attributable to MgSiO 3 attributable to the Mg 2 SiO 4 is less than 1 At this time, a peak attributable to Mg 2 SiO 4 is observed at 2θ = 32.2 ± 0.2 °, a peak attributable to MgSiO 3 is observed at 2θ = 30.9 ± 0.2 °, A cathode active material having a moisture content of less than 200 ppm when measured at 250 ° C. by a karl fisher method, a method for preparing the same, and a cathode including the same are provided. |