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

Abstract

As a potential anode material with high theoretical specific capacity, the practical application of GeO 2 is largely hindered by huge volume change and low reactivity, Herein, we proposed the engineering of dual amorphous GeO 2 @C nanofibers via facile electrospinning and thermal annealing process. In this design, numerous ultrafine GeO 2 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 GeO 2 /C nanofibers render for convenient charge transfer. As a result, the electrode delivers highly reversible conversion (GeO 2 + 4Li ↔ Ge + 2Li 2 O) and alloying (Ge + 4.4Li ↔ GeLi 4.4 ) reaction. Furthermore, the GeO 2 @C nanofibers with large specific surface area also supply more active sites for pseudocapacitive lithium storage. Benefitting from the typical structure, the dual amorphous GeO 2 @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 GeO 2 @C nanofibers competitive electrode material for next-generation lithium-ion batteries. • Dual amorphous GeO 2 @C nanofibers were prepared by a facile and efficient approach. • Dual amorphous GeO 2 @C nanofibers display outstanding lithium storage properties. • Dual amorphous structure benefits for superior lithium storage.