Oxygen Vacancies Boosting Lithium-Ion Diffusion Kinetics of Lithium Germanate for High-Performance Lithium Storage.

Oxygen vacancies play a positive role in optimizing the physical and chemical properties of metal oxides. In this work, we demonstrated oxygen vacancy-promoted enhancement of Li-ion diffusion kinetics in Li2GeO3 nanoparticle-encapsulated carbon nanofibers (denoted as Li2GeO3-x/C) and accordingly boosted lithium storage. The introduction of the oxygen vacancies in Li2GeO3-x/C can enhance electronic conductivity and evidently decrease activation energy of Li-ion transport, thus resulting in evidently accelerated Li-ion diffusion kinetics during the lithiation/delithiation process. Thus, the Li2GeO3-x/C nanofibers exhibit an exceptionally large discharge capacity of 1460.5 mA h g-1 at 0.1 A g-1, high initial Coulombic efficiency of 81.3%, and excellent rate capability. This facile and efficient strategy could provide a reference for injecting the oxygen vacancies into other metal oxides for high-performance anode materials.