Cumulative effects of doping on Sn3O4 structure and electrode performance for rechargeable sodium-ion batteries

Abstract

Tin oxides are the most promising anode materials for sodium-ion batteries (SIBs) owing to their abundance and their multi-electron reactions, which ultimately provide a high theoretical capacity. However, the huge volume expansion and consequent stability issues of tin and tin oxide anodes have relentlessly hindered their application in Na-ion batteries. To overcome these drawbacks, we present a facile strategy to prepare a non-metal-doped Sn₃O₄ anode by facile hydrothermal route and the investigation of its sodium-ion storage performance. B-F@Sn₃O₄ exhibits a triclinic structure with nanoflake morphology, length of 40–100 nm, and thickness of 10–15 nm. When applied as the anode material for SIBs, the resultant material exhibits excellent sodium-ion storage abilities in terms of cycling stability and high rate capability. In SIBs, the Sn₃O₄ anode capacity was observed to be 732.8 mA h g⁻¹ at a current density of 50 mA g⁻¹, and good cycling performance at 200 mA g⁻¹ with a capacity retention of 77.5% after 120 cycles. Furthermore, the diffusion coefficients of the sodium ions calculated based on EIS measurements were observed to be in the range of 10⁻¹³ to 10⁻¹¹ cm² s⁻¹, which reveals the admirable diffusion mobility of Na atoms in the Sn₃O₄ nanoflakes. Moreover, a coin-type sodium-ion full cell consisting of the B-F@Sn₃O₄ anode and a Na₃V₂(PO₄)₃ cathode exhibited a capacity of 81.2 mA h g⁻¹ at C/20. This study demonstrates that the Sn₃O₄ is a promising anode material for SIBs. Thus, the B-F-doped Sn₃O₄ material assembled by interconnected nanoflakes is capable of providing fast carrier transmission dynamics and outstanding structural integrity, suggesting the feasibility of the current framework for sodium-ion storage.