▎ 摘　　要

NOVELTY - A positive electrode comprises a current collector and a positive electrode material layer arranged on one side surface of the current collector. The positive electrode material layer includes a layered transition metal oxide having sodium metal dioxide (I), and a polyanion compound having at least one of sodium phosphate (A), sodium metal oxide (B) and sodium pyrophosphate (C). The mass ratio of the layered transition metal oxide to the polyanion compound is based on the true density (ρ1) of the layered transition metal oxide, and the true density (ρ2) of the polyanionic compound, where the ratio of the true density (ρ1) and the true density (ρ2) is 1.25-1.86. The particle size distribution of the layered transition metal oxide satisfies as given in the specification, and the particle diameter of the polyanionic compound satisfies as given in the specification. USE - The positive electrode is useful in sodium ion battery (claimed), which is useful for continuously developing large-scale energy storage and electric automobile field and electric vehicle. ADVANTAGE - The positive electrode can effectively improve the air stability, simultaneously has higher compaction density and excellent electrochemical performance. DETAILED DESCRIPTION - A positive electrode comprises a current collector and a positive electrode material layer arranged on one side surface of the current collector. The positive electrode material layer includes a layered transition metal oxide having sodium metal dioxide of formula NaxMO2(I), and a polyanion compound having at least one of sodium phosphate of formula NaAPO4(A), sodium metal oxide of formula NayE2(XO4)3(B) and sodium pyrophosphate of formula Na2QP2O7(C). The mass ratio of the layered transition metal oxide to the polyanion compound is based on the true density (ρ1) of the layered transition metal oxide, and the true density (ρ2) of the polyanionic compound, where the ratio of the true density (ρ1) and the true density (ρ2) is 1.25-1.86. The particle size distribution of the layered transition metal oxide satisfies as given in the specification, and the particle diameter of the polyanionic compound satisfies as given in the specification. An INDEPENDENT CLAIM is included for a method for preparing the positive electrode, involving preparing the positive electrode slurry containing a layered transition metal oxide and a polyanion compound, and coating the positive electrode slurry on at least one surface of the current collector, followed by drying and compacting. x = 0.6-1; M = Fe, Mn, Cr, Ni, Co, Cu, Mg, Zr or Ti. A = Fe or Mn; y = 1-4; E = V, Fe, Ni, Mn or Ti; X = P, S ir Si; Q = Fe, Mn or Co.