▎ 摘　　要

NOVELTY - Anode active material comprises sodium-iron-titanium-magnesium phosphate formula of (I), is new. USE - Anode active material for sodium ion battery used as secondary energy storage device in energy automobile, mobile intelligent device, and scale energy storage field. ADVANTAGE - Anode active material is provided with a conductive carbon coating layer with a certain thickness, the doping of Ti and Mg elements can improve the electrochemical performance anode active material, especially the cycle performance and multiplying power performance and divalent Mg will balance the excessive lattice defect caused by tetravalent Ti element doping under the double synergetic effect of titanium and magnesium (Mg) elements, the electro-chemical performance of the phosphate-based sodium ion battery can be obviously improved. DETAILED DESCRIPTION - Anode active material comprises sodium-iron-titanium-magnesium phosphate formula of Na4Fe(3-x1-x2)Tix1Mgx2(PO4)2(P2O7)/C or Na2Fe(1-x3-x4)Tix3Mgx4PO4F/C (I), where x1=0-0.8, x2=0-0.2, x3=0-0.6, and x4=0-0.2, is new. INDEPENDENT CLAIMS are included for: Preparation method of the anode material. Sodium ion battery anode. Sodium ion battery.