Unraveling the impact of metallic Sn on the reversible capacity of passionfruit-like C/SnO2/Sn@C as sodium-ion batteries anodes

Improving the reaction reversibility is a promising way to enhance the sodium-ion storage capability of SnO2-based anodes. In this work, we design the passionfruit-like C/SnO2/Sn@C as a high reversible capacity anode for sodium ion batteries (SIBs). The structural design of the passionfruit-like C/SnO2/Sn@C not only prevents the aggregation of primary SnO2 particles and limits their structural damage, but also finely accelerates electron diffusion rate, avoids interfacial side reactions and achieves the high reversible capacity. Simultaneously, the metallic Sn as a novel additive can accelerate sodium ion diffusion coefficient, and improve the alloying reaction reversibility. Compared to other SnO2-based electrodes, the passionfruit-like C/SnO2/Sn@C structure delivers a high initial coulombic efficiency (78.35%) and excellent reversible capacity (750.8 mAh g−1 at 0.2 A g−1). This work is expected to provide significant enlightenment in the introduction the corresponding metal phase into the metal oxide to enhance the reversible capacity and initial coulombic efficiency of sodium-ion batteries.