Synthesis of three-dimensional rare-earth ions doped CNTs-GO-Fe3O4 hybrid structures using one-pot hydrothermal method

Abstract Rechargeable lithium ion batteries (LIBs) are currently the dominant power source for all sorts of electronic devices due to their low cost and high energy density. The cycling stability of LIBs is significantly compromised due to the broad satellite peak for many anode materials. Herein, we develop a facile hydrothermal process for preparing rare-earth (Er, Tm) ions doped three-dimensional (3D) transition metal oxides/carbon hybrid nanocomposites, namely CNTs-GO-Fe₃O₄, CNTs-GO-Fe₃O₄-Er and CNTs-GO-Fe₃O₄-Tm. The GO sheets and CNTs are interlinked by ultrafine Fe₃O₄ nanoparticles forming three-dimensional (3D) architectures. When evaluated as anode materials for LIBs, the CNTs-GO-Fe₃O₄ hybrid composites have a bigger broad satellite peak. As for the CNTs-GO-Fe₃O₄-Er and CNTs-GO-Fe₃O₄-Tm hybrid composites, the broad satellite peak can be completely eliminated. When the current density changes from 5 C back to 0.1 C, the capacity of CNTs-GO-Fe₃O₄-Tm hybrid composites can recover to 1023.9 mAhg^-1, indicating an acceptable rate capability. EIS tests show that the charge transfer resistance does not change significantly after 500 cycles, demonstrating that the cycling stability of CNTs-GO-Fe₃O₄-Tm hybrid composites are superior to CNTs-GO-Fe₃O₄ and CNTs-GO-Fe₃O₄-Er hybrid structures.