▎ 摘　　要

NOVELTY - Preparing graphene loaded iron oxide involves subjecting graphene powder to thermal gravimetric analysis at heating rate of 5-10degrees Celsius/minutes in oxygen atmosphere to determine its initial weight loss temperature. The graphene powder is placed into high-temperature furnace, passed into oxygen-containing atmosphere at flow rate of 0.01-5 mL/minutes, and temperature is raised to initial weight-loss temperature or slightly exceed initial weight-loss temperature at heating rate of 1-10degrees Celsius/minutes. The heat treatment is maintained for multiple hours, so that certain amount of oxygen-containing functional groups are attached to surface of graphene to obtain graphene with oxygen-containing groups. The graphene with oxygen-containing groups and surfactant are uniformly dispersed in polar solvent with the aid of ultrasound, iron oxide precursor is added to it, and iron oxide precursor is adsorbed on graphene surface by stirring and standing. USE - Method for preparing graphene-loaded iron oxide composite material used in electromagnetic compatibility, lithium ion batteries, and medicine, especially in lithium ion batteries (all claimed). ADVANTAGE - The method enables to provide graphene-loaded iron oxide composite material with improved circulating capacity, high coulomb efficiency and good cycle stability, and method is simple and safe. DETAILED DESCRIPTION - Preparing graphene loaded iron oxide involves subjecting graphene powder to thermal gravimetric analysis at heating rate of 5-10degrees Celsius/minutes in oxygen atmosphere to determine its initial weight loss temperature. The graphene powder is placed into high-temperature furnace, passed into oxygen-containing atmosphere at flow rate of 0.01-5 mL/minutes, and temperature is raised to initial weight-loss temperature or slightly exceed initial weight-loss temperature at heating rate of 1-10degrees Celsius/minutes. The heat treatment is maintained for multiple hours, so that certain amount of oxygen-containing functional groups are attached to surface of graphene to obtain graphene with oxygen-containing groups. The graphene with oxygen-containing groups and surfactant are uniformly dispersed in polar solvent with the aid of ultrasound, iron oxide precursor is added to it, and iron oxide precursor is adsorbed on graphene surface by stirring and standing. A reducing agent is added based on type of target iron oxide to-be-prepared and degree of reduction of graphene, pH regulator is added, and iron oxide precursor is converted into iron oxide in situ through liquid phase reaction to obtain graphene loaded iron oxide composite material.