Construction of hierarchical ZnS/SnO2 @rGO heterostructures as high-performance anode materials for lithium-ion batteries by mixed-precursors strategy

Abstract

The rational design and construction of hierarchical heterogeneous nanostructures is effective for improving the electrical and ionic conductivity of anode material for lithium-ion batteries (LIBs). Herein, a hierarchical ZnS/SnO2 @rGO (rGO = reduced graphene oxide) composite has been designed and successfully synthesized via hydrothermal method by using metal-containing ionic liquid and ZIF-8 metal organic framework precursors. The synergistic effect of precursors hinders the agglomeration of nanoparticles, which makes SnO2 quantum dots (QDs) be anchored on the surface of polyhedral ZnS and further be uniformly dispersed on the rGO. The outer rGO matrix can improve the electrical conductivity and fully alleviate the volume expansion of ZnS/SnO2 during the cycling. Meanwhile, the ZnS/SnO2 heterostructure can endow the material with excellent reaction kinetics, accelerating the charge transfer and providing more active sites for electrochemical reactions. Benefiting from the compositional and structural features, the as-prepared ZnS/SnO2 @rGO as LIB anode provides the reversible specific capacity of 1030 and 630 mA h g−1 after 1150 cycles at the current density of 1.0 and 3.0 A g−1, respectively. This mixed-precursors strategy represents a novel and effective technique to in situ synthesize hierarchical metal sulfide/metal oxide/carbon anode materials for developing high-performance battery.