A novel oxygen vacancy introduced microstructural reconstruction of SnO2-graphene nanocomposite: Demonstration of enhanced electrochemical performance for sodium storage

This paper reported an oxygen vacancy contained SnO2-graphene nanocomposite (OVs-SnO2-Gr), which was prepared by annealing SnO2-graphene nanocomposite in 3 vol% H-2/Ar atmospheres. It demonstrated with a high reversible capacity of around 510 mAh g(-1) after 300 cycles at a current density of 40 mA g(-1), and an impressive reversible rate performance of 391 mAh g(-1) can be obtained even at a high current density of 1200 mA g(-1) when applied as anode for sodium storage. Evidenced by a new phase of Na2SnO3 during sodium storage reactions, it is found that sodium can insert into crystal lattice of oxygen vacancy contained SnO2. Moreover, sodium insertion could arouse a novel structural reconstruction and introduce amorphous phase SnO2, which promotes the surface-controlled reaction process and Na+ diffusion rates, and enables a good rate performance. Additionally, the H-2/Ar annealing process increases overall conductivity of electrodes, which further reduces the barrier of Na+ diffusion. It is believe that the asprepared OVs-SnO2-Gr is a promising anodes for Na-ion batteries with outstanding electrochemical performance. (C) 2018 Elsevier Ltd. All rights reserved.