| 摘要 |
PROBLEM TO BE SOLVED: To provide: a positive electrode material and a paste which are superior in water resistance, high in electron conductivity, and preferably used for a sodium ion secondary battery; and a sodium ion battery.SOLUTION: A positive electrode material comprises carbonaceous electrode active material composite particles each including a positive electrode active material particle including a sodium sulfate compound expressed by NaM(SO)(where M represents one or more than one element selected from a group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd and Ag; 1.6≤x≤2.4; 1.6≤y≤2.4; and 2.4≤z≤3.6) having MOdimer crystal structure in which a dimer is formed by two MO's sharing a ridge in a structure, and a carbonaceous coating covering the surface of the positive electrode active material particle. The carbonaceous coating is formed by a low-temperature process of no higher than 500°C. The coverage of the carbonaceous coating in the surface of each positive electrode active material particle is 60% or more. |
