Facile construction of flower-like MoO2/MoS2 heterostructures encapsulated in nitrogen-doped carbon for high-performance sodium-ion storage

Abstract

The construction of heterostructures in nanostructured anodes has been testified to be a feasible strategy to promote the comprehensive sodium storage properties of sodium-ion batteries, which benefit from the unique synergistic effects and interfacial interactions between different constituents. However, it remains a big challenge to develop simple and cost-effective synthesis methods for rationally building heterostructures within electrode materials. In this study, a facile and cost-effective approach using a hydrothermal method and a subsequent annealing process has been developed to engineer flower-like MoO₂/MoS₂ heterostructures encapsulated in nitrogen-doped carbon (MoO₂/MoS₂@NC) as anodes for sodium-ion batteries. The nitrogen-doped carbon enhances the electrical conductivity and mitigates the huge volume expansion of the electrode materials during the sodiation/desodiation process via the confinement effect. The heterostructure endows the MoO₂/MoS₂@NC anode with rapid Na⁺ diffusion and charge transfer within the electrode, contributing to a fast electrochemical reaction kinetics. Benefiting from the good synergistic effects of different components and unique merits of the heterostructures, the MoO₂/MoS₂@NC anode exhibits favorable sodium storage properties, including high capacity and good rate properties as well as excellent cycling stability.