This work demonstrates a new method for fabrication of mixed metal oxide/oxidized graphene (OGP) composites as flexible and binder-free anode materials for Li-ion batteries. The composites containing nickel manganese ferrite (Ni0.5Mn0.5Fe2O4 (NMFO)) nanoparticles grown on an OGP network structure are fabricated by a facile solvothermal method. In the synthesis, Ni(CH3COO)2, Mn(CH3COO)2, and FeCl3 are used as the metal precursors; CH3COONa, HOCH2CH2OH and distilled water as the mixed solvent. The flexible and binder-free electrodes are prepared by coating OGP and NMFO/OGP on polypropylene microporous film via vacuum filtration. The multilayer and porous structure of the NMFO/OGP film generate good contact between the electrode materials and the current collector (OGP film), which is essential for flexible devices. As anticipated, both the free-standing NMFO/OGP film and NMFO/OGP coated on polypropylene microporous film exhibit super-flexible properties without using any binder. The obtained flexible and binder-free electrodes show good electrochemical performance with high lithium storage capacity and excellent cycling stability. This work opens a new way for fabrication of flexible and binder-free anode materials for Li-ion batteries.