Amorphous carbon nanofibers incorporated with ultrafine GeO2 nanoparticles for enhanced lithium storage performance

As a potential anode material with high theoretical specific capacity, the practical application of GeO2 is largely hindered by huge volume change and low reactivity, Herein, we proposed the engineering of dual amorphous GeO2@C nanofibers via facile electrospinning and thermal annealing process. In this design, numerous ultrafine GeO2 particles are evenly anchored in carbon nanofibers, which could relief the stress in the carbon material during the lithium/delithiation process. Moreover, the low binding energy of Ge-O bond in the dual amorphous GeO2/C nanofibers render for convenient charge transfer. As a result, the electrode delivers highly reversible conversion (GeO2+ 4Li ↔ Ge + 2Li2O) and alloying (Ge + 4.4Li ↔ GeLi4.4) reaction. Furthermore, the GeO2@C nanofibers with large specific surface area also supply more active sites for pseudocapacitive lithium storage. Benefitting from the typical structure, the dual amorphous GeO2@C nanofibers electrode exhibits high reversible capacity of 1053 mAh g−1 at 0.3 A g−1 after 1000 cycle, and superior rate capacity of 476 mAh g−1 at 5 A g−1. The excellent electrochemical performance endows dual amorphous GeO2@C nanofibers competitive electrode material for next-generation lithium-ion batteries. •Dual amorphous GeO2@C nanofibers were prepared by a facile and efficient approach.•Dual amorphous GeO2@C nanofibers display outstanding lithium storage properties.•Dual amorphous structure benefits for superior lithium storage.