SnO2/Sn with core–shell structure Schottky heterojunctions loaded in graphene to promote electrochemical reaction kinetics and enable efficient lithium-ion storage

Abstract

The stannic oxide (SnO₂) anode expands in volume during cycling causing a decrease in reversible capacity. In this work, we generated a spherical SnO₂/Sn heterojunction with core–shell structure composites encapsulated by graphene (SnO₂/Sn/G) in situ using a simple one-step hydrothermal and subsequent annealing process. SnO₂/Sn heterojunction nanospheres dispersed in a porous graphene framework accelerate the diffusion kinetics of electrons and ions. In addition, the structure plays a key role in mitigating large volume changes and nanostructure agglomeration. As a result, SnO₂/Sn/G exhibits excellent performance as an anode material for lithium-ion batteries (LIBs), maintaining a reversible specific capacity of 720.6 mA h g⁻¹ even after 600 cycles at a current density of 0.5 A g⁻¹.