Hierarchical micro-flowers self-assembled from SnS monolayers and nitrogen-doped graphene lamellar nanosheets as advanced anode for lithium-ion battery

Although layered tin sulfide (SnS) nano-architectures are drawing much attention as anode materials in lithium ion batteries (LIBs) because of the high theoretical capacity, there are drawbacks such as the large volume expansion and low conductivity. To overcome these difficulties, attempts have been made to prepare tin sulfide/carbon (SnS/C) nano-hybrids by anchoring/coating nanostructured SnS on/in nano-sized carbon. However, the commonly reported SnS/C composites still suffer from initial Coulombic efficiency (ICE), high electrode swelling, and inferior long-term stability because of weak chemical affinity, and limited contacting interface between SnS and carbon specially at high SnS mass percentage. Herein, we report hierarchical micro-flowers self-assembled from SnS monolayers and nitrogen-doped graphene (NG) lamellar nanosheets (NG-SnS) which are suitable for LIBs anode. The NG-SnS with a high SnS mass percentage (93.9 wt%), obvious C–S bond, and increased contact provide to boost activity, utilization, conductivity, and reversibility of Li storage. Moreover, the elastic NG layers work as a mechanical supporter to decrease the outer volumetric expansion and restrain electrochemical agglomeration of SnS during (de)lithiation processes. The molecular engineered NG-SnS hybrid shows a high initial Coulombic efficiency of 88.2%, robust cycle stability with a high capacity of 790 mAh g⁻¹ after 900 cycles at 0.5 C, considerable rate performance, and small electrode swelling of 12%.