One-pot synthesis of SnS2 Nanosheets supported on g-C3N4 as high capacity and stable cycling anode for sodium-ion batteries

Abstract

Despite being established as the most popular commercial energy storage system (ESS), lithium-ion batteries (LIBs) are still facing practical issues due to their high cost and limited availability of the lithium source. Sodium-ion batteries (SIBs), which have economic and environmental costs, but on-par performance compared to LIBs, are now being considered as the next-generation ESS. Herein, we report a facile and mass-scalable synthesis of SnS2 nanosheets grafting on porous g-C3N4 via direct solid-state reaction from tin (IV) acetate and thiourea as precursors. The synthesized SnS2@g-C3N4 composites served as an anode active material for SIBs with outstanding performances in terms of high capacity and ultralong cycling stability. The optimum anode delivered an initial discharge capacity of 1350.7 mAh g(-1) and the first coulombic efficiency of 55.13%. However, this composite can offer a remarkable charge capacity of 919.6 and 602.7 mAh g(-1) after 400 and 3000 cycles at specific currents of 500 and 2000 mA g(-1), respectively. The enhancement in the cyclability of the obtained composites is attributed to the presence of g-C3N4 as a scaffolding material effectively relieving serious strains induced by the volume variation of SnS2 during sodium storage. The high exfoliation of SnS2 nanosheets with larger interlayer spacing as well as the presence of a self-induced internal electric field formed at the heterointerface of SnS2 and g-C3N4 enables the enhanced transport of electrons and sodium ions, accompanied by the improvement in their electrochemical performance.