Synergistical coupling Janus SnS-Fe1-xS heterostructure cell and polydopamine-derived S doped carbon as high-rate anodes for sodium-ion batteries

Abstract As a potential anode material for sodium-ion batteries, tin sulfide (SnS) has been widely studied. However, sluggish kinetics, severe volume variation, and poor rate performance during cycling greatly hindered its application. Herein, a facile coprecipitation method combining with the carbon coated route and sulfuration process is designed to synthesize a novel SFS@SC nanocube. Unlike previous reports of bimetallic sulfides for sodium-ion batteries, the nanocubes exhibit a nanostructure with heterogeneous SnS/Fe1-xS distribution instead of the aggregation, resembling the double-faced god Janus, and each nanocube could be regarded as a Janus SnS-Fe1-xS heterostructure cell. Owing to the delicate Janus nanoarchitecture with enhanced charge transfer, the SFS@SC exhibits good cycling stability and rate property. In particular, the SFS@SC electrode delivers a high specific capacity of 610 mAh g−1 after 150 cycles at a current density of 0.1 A g−1, and a long cycle life with a capacity of 310 mAh g−1 after 2900 cycles at 2.0 A g−1.