Three-dimensional hollow SnO2@TiO2 spheres encapsulated in reduced graphene oxide aerogels as promising anodes for lithium-ion storage

Abstract Three-dimensional hollow SnO 2 @TiO 2 spheres encapsulated in reduced graphene oxide aerogels (HSTGAs) were successfully fabricated through self-assembly from SnO 2 @TiO 2 hollow spheres and graphene oxide nanosheets using a simple hydrothermal process. The hollow spheres possess an average size of 360 nm. The thickness of SnO 2 shell is 10–15 nm, and the thickness of TiO 2 shell is 20–35 nm. The TiO 2 shell was anchored onto the surface of hollow SnO 2 spheres to effectively limit volume change. Afterward, hollow SnO 2 @TiO 2 spheres were wrapped in graphene oxide nanosheets to build a three-dimensional conductive structure. The applications of HSTGAs as anode for lithium ion storage were explored. Systematic electrochemical results show that HSTGAs electrode maintains a high-discharge capacity of about 668.2 mA h g −1  at 100 mA g −1 after 200 cycles. Compared with pure metal oxide hollow spheres, HSTGAs can greatly enhance the electrochemical performance due to the synergistic effects of metal oxide hollow spheres and graphene oxide nanosheets. HSTGAs are prospective multifunctional nanomaterials that can be used to solve the current energy storage issues.