Bio-inspired hierarchical nanofibrous SnS/C composite with enhanced anodic performances in lithium-ion batteries

Highlights: • Nanofibrous SnS/C composite derived from cellulose substance was bio-synthesized. • The composite possessed a unique hierarchical porous network nanostructure. • Double-protected conductive buffer matrix of carbon core and coating layer was formed. • It exhibited highly-enhanced electrochemical performance as anodic material for LIBs. -- Abstract: Tin sulfide-based anodic materials with high specific capacities for lithium storage have attracted some attentions. Whereas, their poor cycling stability caused by the sever volume variation upon the repeated charge/discharge processes and their intrinsic poor electrical conductivity still need to be solved urgently. Herein, a bio-inspired hierarchical nanofibrous SnS/C composite was synthesized by employing natural cellulose substance as both scaffold and carbon source. Tin oxide gel film was firstly deposited on each cellulose nanofiber through layer-by-layer self-assembly processes, and then the composite was sulfided by hydrothermal treatment followed by carbonization and reduction in Ar atmosphere. The resultant nanocomposite manifests a unique three-dimensional (3D) porous structure composed of interlaced carbon nanofibers anchored with SnS nanoflakes. Used as the anodic material in lithium-ion batteries, the SnS/C composite exhibits remarkable electrochemical performances with a high specific capacity (1396 mAh g⁻¹ in the 1st cycle at 100 mA g⁻¹), long cycle life (612 mAh g⁻¹ after 70 cycles) and good rate capacity (298 mAh g⁻¹ at 1000 mA g⁻¹), which are superior to the nanofibrous SnS₂. The superior anodic performances of the SnS/C composite are mainly due to the 3D hierarchical porous nanostructure and the nanofibrous carbon conductive matrix together with the ultrathin carbon-coating layer, promoting the electrode-electrolyte contact, accommodating the drastic volume changes of SnS, inhibiting the active SnS particles from aggregation and facilitating the electron transfer and lithium-ion diffusion during the charge/discharge processes.