Confined Porous Graphene/SnO_x Frameworks within Polyaniline-Derived Carbon as Highly Stable Lithium-Ion Battery Anodes

Tin oxides are promising anode materials for their high theoretical capacities in rechargeable lithium-ion batteries (LIBs). However, poor stability usually limits the practical application owing to the large volume variation during the cycling process. Herein, a novel carbon confined porous graphene/SnO_x framework was designed using a silica template assisted nanocasting method followed by a polyaniline-derived carbon coating process. In this process, silica served as a template to anchor SnO_x nanoparticles on porous framework and polyaniline was used as the carbon source for coating on the porous graphene/SnO_x framework. The synthesized carbon confined porous graphene/SnO_x frameworks demonstrate substantially improved rate capacities and enhanced cycling stability as the anode materials in LIBs, showing a high reversible capacity of 907 mAh g^-1 after 100 cycles at 100 mA g^-1 and 555 mAh g^-1 after 400 cycles at 1000 mA g^-1. The remarkably improved electrochemical performance could be assigned to the unique porous architecture, which effectively solves the drawbacks of SnO_x including poor electrical conductivity and undesirable volume expansion during cycling process. Consequently, such design concept for promoting SnO_x performance could provide a novel stage for improving anode stability in LIBs.