A new strategy to prepare Ge/GeO2-reduced graphene oxide microcubes for high-performance lithium-ion batteries

Germanium-based materials has been considered as a promising anode material for Li-ion batteries due to their high theoretical capacity. Herein, we reported a novel Ge/GeO2-Reduced graphene oxide (GG-RGO) microcubes via one-step recombination using sodium borohydride as reductant, followed by a calcination process in reducing atmosphere. During the recombination, the reduced graphene oxide coated GeO2 nanoparticles self-assemble to form three-dimensional Ge shell/GeO2 core cubic structure. RGO coated construction can relieve volume expansion, provide a large reactive area and reduce distance for lithium diffusion. Meanwhile, two-phase Ge/GeO2 composite nanostructure can effectively increase specific capacity. Benefited from its unique three-dimensional structure, the Ge/GeO2-RGO composites exhibit high reversible capacity (1005 mAh g(-1) at 100 mA g(-1)), good cycling stability (a high reversible capacity of 933 mAh g(-1) after 50 cycles) and rate performance (740 mAh g(-1) at 2000 mAh g(-1)). (C) 2019 Elsevier Ltd. All rights reserved.