Enhanced Ion/Electron Migration and Sodium Storage Driven by Different MoS2-ZnIn2S4 Heterointerfaces

Constructing hierarchical structures with heterointerfaces is an effective approach for developing high-efficiency energy-storage anodes for sodium-ion batteries. In this study, MoS2@ZnIn2S4 nanorods are designed and fabricated for structural improvement. Theoretical calculations reveal that there are two different MoS2-ZnIn2S4 heterointerfaces formed by MoS2 with the Zn and In facets of ZnIn2S4, which generate directional built-in electric fields that provide additional driving forces for facilitating electron transfer. These two heterojunction interfaces, especially the MoS2-In facet, exhibit enhanced Na+ adsorption energies and reduce Na+ diffusion energy barriers. The multistep reactions of MoS2 and ZnIn2S4 reveal a synergistic effect that promotes the entire electrochemical process. Furthermore, the synthesized hierarchical nanorods composed of nanosheets offer abundant Na+-storage sites and multidirectional migration pathways and, importantly, accommodate the excessive volume change. Benefiting from the heterointerfaces and hierarchical structure, the composite electrode exhibits excellent electrochemical performance, with high reaction activity and rapid electron/ion diffusion kinetics.