Method for preparing fluorine sodium ferrous phosphate porous spongy structure material

The invention relates to a method for preparing a fluorine sodium ferrous phosphate porous spongy structure material. In a sol-gel process, oxalic acid is adopted as a complexing agent and a reducingagent, an organic carbon source is adopted, and a Na2FePO4F porous spongy material is obtained in sol-gel and thermal treatment processes; and primary particles are 10-40nm, the diameters of the porous material particles are micron-scale and are 2-4 microns, and the pore diameters are 400-500nm. The porous spongy structure material is taken as a positive electrode material of a sodium-ion battery;and the performance is tested under the current density of 0.5C (1C=124mA.g) as follows: the initial discharge specific capacity can reach 97.0mAh.g and the specific capacity after 500 cyclescan still reach 73.4mAh.g. The sodium-ion battery has the characteristics of high capacity and good charge-discharge cycle performance. The method is simple in equipment, simple and convenient inprocess, available in raw m