Carbon-coated ReS2 hierarchical nanospheres to inhibit polysulfide dissolution in ether-based electrolytes for high-performance Na-ion batteries

Abstract

In this work, we report a simple hydrothermal route coupled with post-carbonization treatment to synthesize novel ReS₂/C hierarchical nanospheres as an advanced sodium storage anode in ether-based electrolytes (EBEs). In the ReS₂/C architectures, few-layered ReS₂ nanosheets with an expanded interlayer spacing of 0.67 nm are self-assembled to form hierarchical nanospheres, providing a robust structure and a large surface area that facilitate electrolyte contact in sodium-ion batteries (SIBs). The amorphous carbon coating plays key roles in not only improving the electronic conductivity but also inhibiting the shuttle effect of polysulfides in EBEs, which results in superior high-rate capability and excellent cyclability. Consequently, the ReS₂/C anode yields a high specific capacity of 185 mA h g⁻¹ at an ultra-high current density of 20 A g⁻¹ and maintains a specific capacity of 209 mA h g⁻¹ after undergoing 3000 cycles at 10 A g⁻¹ as the highest current density for long-term cycling to date. Compared with carbonate-based electrolytes (CBEs), the ReS₂/C anode containing EBEs shows a significantly prolonged cycling lifespan and improved high-rate capability. Moreover, the Na₃V₂(PO₄)₃∥ReS₂/C full cell is demonstrated for the first time and delivers decent cycling performance of 300 cycles at 1C with a capacity retention of 95.9%. Our work provides new insight into enhancing the sodium storage performance of ReS₂-based anodes by nanoscale engineering and electrolyte modulation.