Sodium-ion storage mechanism of hierarchical Bi2SiO5/rGO nanoflower

Synthesis of hierarchical interwoven nanoflower Bi 2 SiO 5 /rGO composite. • In situ XRD shows conversion-alloying Na⁺ storage mechanism of Bi 2 SiO 5 . • Reversible Bi alloying in Bi 2 SiO 5 /rGO sustains 198 mAh g –1 after 100 cycles. • Irreversible conversion forms stable Bi/Na 2 O/SiO 2 nanocomposite for reversible Bi alloying. Sodium-ion batteries (SIBs) have emerged as an alternative to lithium-ion batteries due to their abundant resources and low cost. However, developing anode materials compatible with the larger ionic radius of sodium remains challenging. This study proposes a Bi 2 SiO 5 /reduced graphene oxide (rGO) composite constructed by hierarchically stacked nanosheets as an anode for SIBs. The Bi 2 SiO 5 /rGO electrode delieves rate capability with reversible capacities of 279.6, 266.9, 237.4, 174.7, and 131.1 mAh g –1 at current densities of 20, 50, 100, 200, and 500 mA g –1 , respectively. Furthermore, the material retains a specific capacity of 198.3 mAh g –1 after 100 cycles when tested at a current density of 50 mA g –1 . In addition, in-situ X-ray diffraction (XRD) analysis revealed that the material underwent conversion and alloying reactions during sodiation and desodiation. Meanwhile, the full cell assembled with this material exhibited a reversible capacity of 78 mAh g –1 after 30 cycles. These results provide insights for the development of bismuth-based anode materials sodium-ion batteries. A Bi 2 SiO 5 /rGO anode with a three-dimensional porous nanosheet architecture is reported. This anode exhibits rate capability and cycling stability. The sodium storage mechanism of Bi 2 SiO 5 was investigated using in situ XRD, and a full cell was constructed to evaluate its practical feasibility. Download: Download high-res image (186KB) Download: Download full-size image