Homogeneous slate-like nitrogen-doped carbon/SnS composites constructed by in-situ carbonization and vulcanization as high-performance anode materials for sodium-ion batteries

Abstract

SnS possesses a unique layered structure, which makes it suitable as an anode for sodium-ion batteries (SIBs). However, the low intrinsic electronic conductivity limits its further development. The use of interface coatings can effectively mitigate this problem, and carbon coatings are a good choice. In our work, Sn-MOF containing S was calcined in an inert atmosphere to achieve synchronous carbonization and vulcanization, and the homogeneous slate-like nitrogen-doped carbon /SnS (N-C/SnS) composites were synthesized in-situ. The slate-like structure makes the anodes solid for long durability. The homogeneous growth of N-doped C and SnS strengthens the mechanical stability of SnS as well as greatly enhances the conductivity. The N-doped C framework can induce the formation of excessive active sites for Na+ insertion. The N-C/SnS-500 electrode can still reach 293 mA h g−1 capacity after 1600 cycles at 5 A/g as SIBs anode materials, showing outstanding cycle-to-cycle stability. It is exciting to note that a sodium-ion full cell with the N-C/SnS-500 anode can still provide a capacity of 183 mA h g−1 after 1200 cycles at 0.5 A/g. This work has guiding significance for the homogeneous synthesis of carbon/metal sulfide composites and the regulation of their electrochemical properties.