▎ 摘　　要

NOVELTY - A ferroferric oxide/graphene three-dimensional composite structure comprises ferroferric oxide/graphene, three of four spherical iron oxide with diameter of 180-700 nm, and hierarchical structure, where the hierarchical structure is formed by assembly of primary particles, three-dimensional network of graphene covered with ferroferric oxide particle o form a stable composite structure, and the concentration of the graphene is 0.6-6 mass%. USE - Ferroferric oxide/graphene three-dimensional composite structure for use in a negative electrode of a lithium ion battery (all claimed). ADVANTAGE - The composite structure improves conductivity of the electrode, buffers volume expansion of ferroferric oxide in the charge-discharge cyclic process, contributes to self-formation of ferroferric oxide into submicron particles with uniform sizes, and improves the electrochemical performance of electrode, and is simple, easy, and environment-friendly to prepare. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following: (1) a method for preparing a ferroferric oxide/graphene three-dimensional composite structure (2) a negative electrode (3) a lithium ion battery.