Preparation And Properties Of Iron Oxide As Anode Material For Lithium Ion Battery

The anode electrode material of lithium ion battery has the advantages of high theoretical specific capacity,rich raw materials and low cost,simple preparation process,and has certain development potential and application prospect in the field of lithium ion battery electrode material.In this paper,nano-α-Fe2O3 anode electrode material and Fe3O4/C composite anode electrode material were prepared by sol-gel-auto-combustion method,and Fe3O4/C anode electrode material was prepared by high temperature mechano-chemical method.The preparation process and electrochemical properties of the materials were studied by means of XRD,SEM and constant current charge-discharge test.The optimum preparation conditions for preparation of nano-α-Fe2O3 anode electrode materials by Sol-gel-auto-combustion method were determined,n citric acid/n ferric nitrate=2.75:1,reaction temperature 500℃,holding time 100 min.At 0.05～3 V and 0.2 C,the first cycle discharge specific capacity of nano-α-Fe2O3 material was 969 mAh·g-1.After 20 cycles,the discharge specific capacity was 139 mAh·g-1.The optimum preparation conditions for preparation of Fe3O4/C composite anode electrode materials by sol-gel-auto-combustion method were determined,the mass ratio of nano-α-Fe2O3 to sucrose 1:1,the reaction temperature 600℃,the holding time 6 h,argon atmosphere.The charge-discharge test and cyclic performance test showed that the discharge ratio capacity of Fe3O4/C composite material was 1114 mAh·g-1.After 70 charge-discharge cycles,the discharge specific capacity was 523 mAh·g-1.According to the performance test,when the charge-discharge ratio was 0.2,0.4,0.6,0.8,1,2 C,the discharge specific capacity of the cell at each rate was 1100,463,339,244,201,111 mAh·g-1,and then the discharge specific capacity of the material can be stabilized at 425 mAh·g-1 at 0.2 C,The CV test showed that the material had an oxidation peak at 1.7 V,reduction peaks appears at 0.5 V,EIS test showed that the charge transfer resistance Rct=91.3 Ω,it is far lower than that of common Fe3O4 crystal material.The optimum preparation conditions of Fe3O4/C composite anode electrode materials by high temperature mechano-chemical method were determined,ball grinding temperature 600℃,raw material mass ratio 3:2,ball grinding time 6 h,ball material ratio 30:1,argon atmosphere.When the charge-discharge test and cyclic performance test were conducted at 0.05-3 V and 0.2 C,the first cycle discharge specific capacity of Fe3O4/C composite anode electrode material was 1001 mAh·g-1.After 20 cycles,the discharge specific capacity was 306 mAh·g-1.