Freeze‐Drying‐Assisted Synthesis of Porous SnO2/rGO Xerogels as Anode Materials for Highly Reversible Lithium/Sodium Storage

Abstract Three‐dimensional porous SnO 2 /rGO xerogels with superior cycling performance in lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs) are fabricated through a freeze‐drying‐assisted method. SnO 2 nanoparticles (5 nm in diameter) are homogeneously attached to the surface of graphene sheets without self‐aggregation. The heterostructured SnO 2 /rGO xerogel possesses numerous micron‐sized pores that can efficiently buffer the volumetric change of SnO 2 during the charge/discharge process and provide multidimensional channels, improving the conductivity between active materials and electrolyte. The SnO 2 /rGO xerogel exhibits excellent electrochemical performance, both in LIBs and SIBs, owing to its particular porous structure. For LIBs, it delivers a high initial discharge capacity of 1670.5 mAh g −1 in the first cycle and remains at 1139.4 mAh g −1 after 166 cycles at a current density of 0.1 A g −1 . The SnO 2 /rGO xerogel also delivers a high discharge capacity of 189.4 mAh g −1 without capacity loss over 266 cycles at a current density of 0.5 A g −1 for SIBs. The SnO 2 /rGO xerogel can be used as an electrode material in both LIBs and SIBs, and can maintain an excellent rate performance and cyclic performance, owing to the abundant porosity and high conductivity.