Hydrothermal synthesis of SnO2/MoO3-x/rGO ternary nanocomposites as a high-performance anode for lithium ion batteries

Abstract

The theoretical specific capacity of tin dioxide (SnO2) as a lithium-ion batteries (LIBs) anode material is up to 1494 mAh·g−1, far exceeding that of graphite. However, the low conductivity, volume expansion, crushing failure and particles agglomeration during charge/discharge cycles limit its application in LIBs. In this work, the SnO2/MoO3-x/rGO composite material was synthesized by one-step hydrothermal method, with SnO2 and amorphous MoO3-x tightly and uniformly anchored at the surface of reduced graphene oxide (rGO). The results of structural characterization and electrochemical performance evaluation show that amorphous MoO3-x can increase the reactive active sites, inhibit Sn particles aggregation, and promote the reversible reaction of SnO2. rGO effectively improves the electrical conductivity of the composite and buffers the volume change of Li-Sn alloying/dealloying during cycles. In addition, due to introduction of MoO3-x and rGO a stable SEI film can be formed at the material's surface to improve the cycle stability. SnO2/MoO3-x/rGO exhibits excellent rate performance and cycle performance. When the rGO content is 10.9 wt%, the reversible capacity of the composite reach 813 mAh·g−1 after 800 cycles at current density of 1.0 A·g−1, and 450.6 mAh·g−1 after 1000 cycles at current density of 5.0 A·g−1, with the capacity retention rate of 96.9%.