High-Capacity and Ultrafast Na-Ion Storage of a Self-Supported 3D Porous Antimony Persulfide-Graphene Foam Architecture.

The key challenge for high-performance sodium-ion batteries is the exploitation of appropriate electrode materials with a long cycling stability and high rate capability. Here, we report Sb2S5 nanoparticles (∼5 nm) uniformly encapsulated in three-dimensional (3D) porous graphene foam, which were fabricated by a facile hydrothermal coassembly strategy, as a high-performance anode material for sodium-ion batteries. The as-prepared composite can be directly used as electrodes without adding a binder or current collector, exhibiting outstanding electrochemical performance with a high reversible capacity (845 mA h g-1 at 0.1 A g-1), ultralong cycling life (91.6% capacity retention after 300 cycles at 0.2 A g-1), and exceptional rate capability (525 mA h g-1 at 10.0 A g-1). This is attributed to fast Na+ ion diffusion from the ultrasmall nanoparticles and excellent electric transport between the active material and 3D porous graphene, which also provide an effective strategy for anchoring the nanoparticles. Experimental results show that the Sb2S5 undergoes a reversible reaction of Sb2S5 + 16Na ↔ 5Na2S + 2Na3Sb during sodiation/desodiation. Moreover, a full cell with Na3(VO0.5)2(PO4)2F2/C cathode and the as-prepared composite anode was assembled, displaying high output voltage (∼2.2 V) with a stable capacity of 828 mA h g-1 for anode material (with 100 cycles at 0.1 A g-1), showing the potential for practical application.