Ball-in-ball SnO2/SnS@Void@C as anodes for enhanced electrochemical performances of Li/Na-ion batteries

Abstract

On account of their significant theoretical capacities, tin-based compounds have garnered substantial attention as anode materials for alkali metal secondary batteries including lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). In this study, SnO₂/SnS hollow heterogeneous spheres were confined to grow within hollow carbon spheres to form a ball-in-ball structure of SnO₂/SnS@Void@C using a confinement sacrifice template synthesis strategy. The ball-in-ball structure with free nanometer gaps not only offered mesoporous channels to promote ion transport, but also provided plenty of buffer space to relieve SnO₂/SnS volume expansion, thus improving cycling stability and rate performance. When SnO₂/SnS@Void@C was used as an anode material in LIBs and SIBs, the discharge capacities of LIBs and SIBs after 500 cycles were 415 mA h g⁻¹ and 303 mA h g⁻¹ at 5 A g⁻¹, respectively. The remarkable electrochemical performance of the structure underscores its significant potential for energy storage applications and serves as a valuable reference for the strategic design of double-layer hollow spheres.