Stabilizing the nanostructure of SnO_2 anode by constructing heterogeneous yolk@shell hollow composite

摘要

Herein, to effectively stabilize the nanostructure of SnO2 anode during long repeated discharge/charge process, a well-designed TiO2@Void@SnO2@C hollow nanospheres (defined as TiO2@Void@SnO2@C HNSs) composite with a distinctive heterogeneous yolk@shell hollow nanostructure has been prepared. The TiO2@Void@ SnO2@C HNSs consists of core@shell SnO2@C hollow nanospheres (shells) with built-in TiO(2 )hollow nanospheres (yolks) (namely, TiO(2 )hollow nanospheres in SnO2@C hollow nanospheres). Thus, the TiO2@Void@ SnO2@C HNSs has three main advantages in lithium storage in terms of structure. Firstly, the TiO2, as a robust built-in structure support, can restrain SnO2 from collapsing inward into the hollow cavity. Secondly, the inherently adequate free space including void (between shells and yolks) and hollow cavity as well as flexible carbon coating can accommodate the volume variation of SnO2, and therefore boosts the structural stability of whole composite. Finally, the good conducive carbon coating can improve the conductivity of entire composite, hence promotes the electrochemical reaction kinetics of lithium storage. As a result, the TiO2@Void@SnO2@C HNSs delivers a high capacity of 662 mAh g(-1) after even 500 cycles as well as good rate properties, showing outstanding lithium storage performance as well as great potential as a high-performance anode for lithium-ion batteries.