A novel self-assembled LiFePO4/graphene composite is successfully prepared by a facile template-free hydrothermal approach. Physical and electrochemical properties of the LiFePO4/graphene composite as cathode material in rechargeable hybrid aqueous batteries are firstly investigated. The LiFePO4/graphene composite exhibits a high discharge capacity of 145.8mAhg−1 at 0.2C, which is 40% higher than that of pristine LiFePO4. Moreover, LiFePO4/graphene shows much better rate capability and excellent cyclability. This enhanced electrochemical performance could be attributed to the positive effects of graphene nanosheets, which create a flexible electrical conductive matrix, ensuring a continuous electron pathway in bulk electrode and absorbing the volume change during lithium intercalation/de-intercalation of LiFePO4. •A self-assembled LiFePO4/graphene composite is prepared by a hydrothermal method.•The LiFePO4 particles with rough surface are composed of numerous nanoparticles.•LiFePO4 particles are distributed uniformly among the wrinkled graphene sheets.•LiFePO4/graphene shows superior properties in rechargeable hybrid aqueous battery.