Uniform yolk-shell Fe2O3@N-doped carbon nanorings with rich oxygen vacancies as anode materials for high performance Li-ion battery

Abstract

Owing to the rapidly increasing demand of energy storage devices, it is necessary to create an apposite anode of lithium ion batteries (LIBs). Fe2O3-based anode materials, which possess high theoretical capacity and low cost, are one of the popular candidate anodes. However, Fe2O3-based anode suffer from large volume change and low conductivity. Herein, yolk-shell (YS) Fe2O3/N-doped carbon nanorings with abundant oxygen vacancies (YS-Fe2O3@NC-OVs) were designed and synthesized for robust lithium storage. OVs in the Fe2O3 lattices were introduced by annealing process, inducing a local construction internal electric field to accelerate the fast migration of Li+ by Coulomb force during cycling process and leading to an excellent electrochemical property for Li-ion batteries. Benefit from the yolk-shell structure and the OVs, the YS-Fe2O3@NC-OVs electrode display an outstanding cycling stability with a reversibly specific capacity of 697.4 mA h g−1 at 5 A g−1 after 500 cycles for lithium storage. And a high specific capacity of 570.3 mA h g−1 at 10 A g−1 is attained. The high reversible specific capacities and superior cycle stability of YS-Fe2O3@NC-OVs might be ascribed to the elaborate YS nanoarchitecture. The well-designed YS nanoarchitecture might be to blame for the high reversible specific capacities and remarkable cycle stability of YS-Fe2O3@NC-OVs. Additionally, the work function (WF) indicated that the enhanced lithium storage performance of YS-Fe2O3@NC-OVs might be ascribed to better Li+ diffusion kinetics and high electronic conductivity.