Three-dimensional hierarchical mesoporous rose-like SnSe2/N-doped carbon anode materials for long-life sodium ion batteries

Abstract

Sodium-ion batteries (SIBs) show significant promise for large-scale energy storage applications, owing to their plentiful resources and environmental advantages. However, their practical deployment faces challenges primarily due to inadequate rate performance and cycling stability. A key factor contributing to these issues is the larger size of Na-ions, which leads to diminished structural integrity and slower reaction kinetics. However, ongoing research and development efforts are paving the way for overcoming these challenges, bringing SIBs closer to becoming a viable alternative to Li-ion batteries (LIBs) in various applications. In this study, three-dimensional hierarchical mesoporous rose-like SnSe₂@N-doped carbon (RL-SnSe₂@NC) was fabricated using solvothermal and selenizing techniques. Consequently, RL-SnSe₂@NC demonstrated an exceptionally high specific capacity of 332.8 mA h g^-1 for SIBs at a rate of 5 A g^-1 after 3000 cycles. Ex situ XRD, XPS, HRTEM and SAED analyses were conducted to investigate the changes in crystal structure that occur between sodium (Na) and SnSe₂ during the charge and discharge processes. Furthermore, when paired with Na₃V₂(PO₄)₃ (NVP) as the cathode in a sodium-ion full cell, the optimized configuration featuring RL-SnSe₂@NC as the anode demonstrates outstanding performance. Notably, this remarkable material attains an impressive capacity of 220.9 mAh g^-1 at a current density of 1 A g^-1, operating within the voltage range of 0.5 to 4.0 V.