Investigation on the effect of metal incorporation in metal selenide nanoparticles and their encapsulation in hollow carbon nanospheres on improving the sodium-ion battery performance

Abstract

Rationally designed nanostructured electrode materials demonstrate outstanding sodium-ion storage performance. Among these, yolk-shell configurations of metal chalcogenide@void@carbon are particularly effective as high-performance anode materials for sodium-ion batteries. In this study, yolk-shell-structured nanospheres featuring metal-incorporated metal selenide nanoparticles (yolk) encapsulated within hollow mesoporous carbon spheres (shell) were successfully fabricated using salt infiltration and a one-step post-treatment. Hollow mesoporous carbon spheres serve as structural frameworks, provide conductive pathways, and limit the excessive growth of metal selenide particles during thermal treatment. By incorporating transition metal in metal selenides, the electronic structure was rationally tailored to enhance their intrinsic electrical conductivity, sodiumion storage performance, and reaction kinetics. This uniquely designed composite demonstrates exceptional electrochemical performance, delivering a high discharge capacity after 150 cycles at 0.5 A g-1 and an impressive rate capability at a current density of 3.0 A g-1, making it a promising candidate as sodium-ion battery anode. Encapsulating metal-incorporated metal selenide nanoparticles within hollow carbon nanospheres with relatively higher electronic conductivity effectively alleviated the volume changes that occur during cycling and enabled accelerated electrochemical kinetics. The origin of the enhanced electrochemical performance was traced down systematically with both experiments and theoretical calculations.