*2.1. Fabrication*

The SnS/C nanopowders were fabricated using either artificial graphite (AG) or microcarbon microbeads (MCMB) as the matrix, as both have very good electrochemical properties [12]. Both MCMB and AG were purchased, rather than being synthesized in the lab.

The synthesis of the composite SnS/C materials was carried out using electroless deposition, similar to the processes reported in [13]. SnCl2·2H2O (99.9%, Fluka, Charlotte, NC, USA) and NH2CSNH2 (99.0%, Merck, Kenilworth, NJ, USA) were used as the metal ion precursors, while AG or MCMB were used as the carbon precursors. The metal ion precursors were refluxed with the carbon in 100mL ethylene glycol (99.9%, J.T. Baker, Radnor, PA, USA) at 200 ◦C for 8 h. The precipitate obtained was collected by centrifugation and washed using ethanol. Finally, the product was dried at 70 ◦C for 2 h to obtain the final powders.

In order to evaluate the effect of SnS content on the electrochemical performance, two different amounts (10% or 20%) of SnS were considered. For the case of 10%Sn10%S/C (abbreviated as 10SnS/C), the solution contained the inorganic materials in the proportion of 0.1 g Sn atoms and 0.1 g S atoms for every 0.8 g C atoms. Similarly, for the 20%Sn20%S/C (abbreviated as 20SnS/C), the solution contained 0.2 g Sn atoms and 0.2 g S atoms for every 0.6 g of C atoms.
