Facile synthesis of SnS2@g-C3N4 composites as high performance anodes for lithium ion batteries

[Display omitted] •Facile one-step synthesis of the SnS2@g-C3N4 composites.•Significant enhancement in the electrochemical performance of the SnS2@g-C3N4 composites.•Large contribution of pseudocapacitive effect.•Clarifying the lithium storage mechanism of the SnS2@g-C3N4 composites. Today, the demand of high performance and low-cost anodes for lithium ion batteries becomes more serious to meet the requirement of electric vehicles and portable devices. In this study, a facile synthesis technique using a solid state reaction has been successfully applied for SnS2@g-C3N4 composites. The obtained composites are constructed by SnS2 nanosheets well-dispersed in porous matrix of g-C3N4. The enhancement in the specific capacity, rated performance, and cycling behavior of the SnS2@g-C3N4 composites is assigned to the buffering effect of the large-surface-area g-C3N4 matrix as well as the predominant contribution of pseudocapacitive effect. The improved mobility of charge carriers is raised from not only the high exfoliation of the SnS2 nanosheets, the high porosity of the composites but also the formation of heterointerfaces between semiconductors of SnS2 and g-C3N4. Accordingly, an internal electric field is generated inside the synthesized composites, which accelerates the migration of electrons and lithium ions.