Reduced Graphene Oxide-Supported SrV₄O₉ Microflowers with Enhanced Electrochemical Performance for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) have received considerable attention in recent years. Anode material is one of the key factors that determine SIBs’ electrochemical performance. Current commercial hard carbon anode shows poor rate performance, which greatly limits applications of SIBs. In this study, a novel vanadium-based material, SrV₄O₉, was proposed as an anode for SIBs, and its Na⁺ storage properties were studied for the first time. To enhance the electrical conductivity of SrV₄O₉ material, a microflower structure was designed and reduced graphene oxide (rGO) was introduced as a host to support SrV₄O₉ microflowers. The microflower structure effectively reduced electron diffusion distance, thus enhancing the electrical conductivity of the SrV₄O₉ material. The rGO showed excellent flexibility and electrical conductivity, which effectively improved the cycling life and rate performance of the SrV₄O₉ composite material. As a result, the SrV₄O₉@rGO composite showed excellent electrochemical performance (a stable capacity of 273.4 mAh g⁻¹ after 200 cycles at 0.2 A g⁻¹ and a high capacity of 120.4 mAh g⁻¹ at 10.0 A g⁻¹), indicating that SrV₄O₉@rGO composite can be an ideal anode material for SIBs.