Engineering design of graphene tightly wrapped hollow structure for boosted lithium storage in conversion/alloying electrode: A case of SnO2

Abstract

Developing cost-effective and high-performance conversion/alloying anode materials in lithium-ion batteries (LIBs) depend on the exquisite design of nanostructure that can efficiently improve volume change and enhance lithium storage capability of active materials. Herein, taking the typical SnO2 as an example, a universal strategy has been proposed to solve many difficulties faced by these electrode materials, i.e. in situ encapsulating hollow SnO2 nanospheres into sack-like reduced oxide graphene nanosheets (SnO2@RGO). This simple and ingenious design combines the flexibility of external graphene and the hollow characteristics of internal SnO2, thus providing more insertion sites and greatly avoiding the occurrence of structural collapse caused by large volume changes upon cycling. As expected, the SnO2@RGO electrode shows a larger initial discharge capacity, better capacity retention and more remarkable rate capability as compared to pristine SnO2 nanospheres electrode when used as advanced anode for LIBs.