Design and synthesis of porous nano-sized Sn@C/graphene electrode material with 3D carbon network for high-performance lithium-ion batteries

Tin is a promising high-capacity anode material for lithium-ion batteries, but it usually suffers from the problem of poor cycling stability due to the large volume change during the charge-discharge process. In this article, porous nano-sized Sn@C/graphene electrode material with three-dimensional carbon network was designed and prepared. Reducing the size of the Sn particles to nanoscale can mitigate the absolute strain induced by the large volume change during lithiation-delithiation process, and retard particle pulverization. The porous structure can provide a void space, which helps to accommodate the volume changes of the Sn nanoparticles during the lithium uptake-release process. The carbon shell can avoid the aggregation of the Sn nanoparticles on the same piece of graphene and detachment of the pulverized Sn particles during the charge-discharge process. The 3D carbon network consisted of graphene sheets and carbon shells can not only play a structural buffering role in minimizing the mechanical stress caused by the volume change of Sn, but also keep the overall electrode highly conductive during the lithium uptake-release process. As a result, the as-prepared Sn@C/graphene nanocomposite as an anode material for lithium-ion batteries exhibited outstanding cyclability. The reversible specific capacity is almost constant from the tenth cycle to the fiftieth cycle, which is about 600 mA h g 1. The strategy presented in this work may be extended to improve the cycle performances of other high-capacity electrode materials with large volume variations during charge-discharge processes. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.