SnS2/g-C3N4/graphite nanocomposites as durable lithium-ion battery anode with high pseudocapacitance contribution

Tin disulfide is a promising anode material for Li-ion batteries (LIB) owing to its high theoretical capacity and the abundance of its composing elements. However, bare SnS 2 suffers from low electrical conductivity and large volume expansion, which results in poor rate performance and cycling stability. Herein, we present a solution-based strategy to grow SnS 2 nanostructures within a matrix of porous g-C 3 N 4 (CN) and high electrical conductivity graphite plates (GPs). We test the resulting nanocomposite as anode in LIBs. First, SnS 2 nanostructures with different geometries are tested, to find out that thin SnS 2 nanoplates (SnS 2 -NPLs) provide the highest performances. Such SnS 2 -NPLs, incorporated into hierarchical SnS 2 /CN/GP nanocomposites, display excellent rate capabilities (536.5 mA h g −1 at 2.0 A g −1 ) and an outstanding stability (∼99.7% retention after 400 cycles), which are partially associated with a high pseudocapacitance contribution (88.8% at 1.0 mV s −1 ). The excellent electrochemical properties of these nanocomposites are ascribed to the synergy created between the three nanocomposite components: i) thin SnS 2 -NPLs provide a large surface for rapid Li-ion intercalation and a proper geometry to stand volume expansions during lithiation/delithiation cycles; ii) porous CN prevents SnS 2 -NPLs aggregation, habilitates efficient channels for Li-ion diffusion and buffer stresses associated to SnS 2 volume changes; and iii) conductive GPs allow an efficient charge transport.