Neurons-system-like structured SnS₂/CNTs composite for high-performance sodium-ion battery anode

Sodium-ion batteries (SIBs) have attracted significant attention with respect to renewable energy power generation systems because of the abundant reserves of sodium on earth. However, anode materials are presently limited by low energy density, poor rate performance and inferior cycling stability. In recent years, tin disulfide (SnS₂) with a particular layered structure has been considered as a promising anode material for SIBs due to its high theoretical capacity and low cost. Herein, a nervous-system-like structured SnS₂/CNTs composite was successfully synthesized via a hydrothermal method. The SnS₂ sheets were strung with carbon nanotubes (CNTs) to form a hierarchical porous structure, which is effective for electrolyte diffusion and electronic transmission. The large distance of the (001) plane (0.5899 nm) of SnS₂ favors Na⁺ insertion–extraction dynamics. Benefitting from these structural characteristics, SnS₂/CNTs electrodes exhibit high specific capacity, excellent rate performance and superior cycling stability. A high charge capacity of 642 mAh·g⁻¹ was released at 0.2 A·g⁻¹, and then, a high reversible capacity of 427 mAh·g⁻¹ was retained after 100 cycles. Even charged at 2 A·g⁻¹, the SnS₂/CNTs electrode maintained a capacity of 282 mAh·g⁻¹. The nervous-system-like structure of the SnS₂/CNTs composite provides a novel strategy for the development of SIBs with high electrochemical performance.