A Facile Approach to Construct Yolk-Shelled Sno2@Nxc Electrode and its Enhanced Performance

Abstract

A facile and universal route has been developed to synthesize metal oxides-based yolk-shelled structures with controllable void size. Based on this approach, a yolk-shelled SnO 2 @N dopped C (yolk-shelled SnO 2 @NxC) composite has been successfully synthesized for lithium-ion battery electrodes. The reported yolk-shelled SnO 2 @NxC, with SnO 2 as inner shell and core, can remarkably increase the volumetric energy density of electrodes. The void between shell and core could accommodate the volume expansion during lithiation, while the NxC outer layer as a framework maintains the structure's integrity and shortens the transmission distance of charges. The results confirm the much-improved electrochemical performance. The yolk-shelled SnO 2 @NxC electrode delivers excellent cycling stability of 740 mAh g -1 at a current density of 0.25 C after 750 cycles and a superior rate performance of 500 mAh g -1 at 5C (1 C=800 mA g -1 ). Furthermore, some other yolk-shelled metal oxides such as yolk-shelled TiO 2 and yolk-shelled Fe 2 O 3 also have been directly synthesized through the method in this paper for their proper applications.

Keywords: yolk-shelled structures, Lithium-Ion Batteries, SnO2, anodes, volume expansion