Flexible nitrogen-doped graphene/SnO2 foams promise kinetically stable lithium storage

In developing high-performance electrode materials for lithium-ion batteries, building kinetically stable graphene-SnO2 anode is appealing yet remains challenging. Here we demonstrate a balanced design of graphene-SnO2 composite, i.e., a flexible nitrogen-doped graphene/SnO2 (NG-SnO2) foam with an integrated macroscale film and interconnected micro-/nano-foam architecture. The combined favorable structure and components improve the Li+ accessibility and electron transmission, while prevent side reactions with the electrolyte and SnO2. Notably, a novel electrochemistry is triggered by the synergistic effect between SnO2 and graphene, i.e., irreversible conversion reaction of SnO2 becomes reversible upon cycling. These efforts lead to an ascending capacity with the increment of >1000 mA h g(-1). The composite foam can retain more than 81% of its initial capacity to 1678 mA h g(-1) over cycles of 8.5 months at a rate of 0.1 A g(-1), exhibiting kinetically-stable electrochemical performances. (C) 2015 Elsevier Ltd. All rights reserved.