Encapsulation of SnO_2 nanoparticles into hollow TiO_2 nanowires as high performance anode materials for lithium ion batteries

摘要

In this work, a new nanostmcture of SnO_2 nanoparticles (NPs) encapsulated into hollow TiO_2 nanowires (SnO_2@TiO_2) has been successfully fabricated. This unique architecture intrinsically possess void space in between the TiO_2 shell and SnO_2 nanoparticle cores, as confirmed by XRD, XPS, SEM, TEM and HRTEM characterizations. The TiO_2 shell of the composite can not only alleviate the pulverization and drastic volume change of the SnO_2 NPs and maintain the structural integrity, but also contribute to the total capacity of the composite. Moreover, the void space can also accommodate the volume expansion of SnO_2 and provide highly efficient channels for the fast transport of both electrons and lithium ion during discharge/ charge cycling process. When tested as potential anode materials for lithium ion batteries, the as-prepared hollow TiO_2 nanowires shell encapsulating SnO_2 NPs architecture exhibits good lithium storage performance and excellent cyclability (which delivers a higher reversible capacity of 445 mAh g~(-1) at 800 mA g~(-1) after 500 cycles). The unique architecture should be responsible for the superior electrochemical performance.