SnS2 nanodots decorated on RGO sheets with enhanced pseudocapacitive performance for asymmetric supercapacitors

The SnS2/rGO composite was demonstrated with sphere-like structure assembled by SnS2/rGO sheets. Each SnS2/rGO sheet was characterized with the negative electricity of reduced graphene oxide (rGO) causing monodisperse SnS2 nanodots to be anchored uniformly on its surface. The First-principle calculation of the SnS2/rGO indicated smaller band gap and increased free electrons in the SnS2/rGO composite, confirming favorable electron transfer in the composite. The synergistic effect between SnS2 and rGO rendered the composite electrode with high specific capacitances (871.7 C g(-1) at 1 A g(-1)), high cyclic stability (retention of 94.9% after 1000 cycles) and excellent rate performance. The SnS2/rGO composite was also used as the positive electrode for an asymmetric supercapacitor (ASC), which can deliver promising capacitances, energy densities and power densities. High cyclability was also delivered with high capacitance retention of 95.1% after 5000 cycles. The ASC device was then used to light up a blue LED, which can be lighted for more than 12 min with a 20s charge of the ASC, implying promising prospect for future energy storage devices. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The SnS2/rGO composite with sphere-like structure shows high specific capacitance and excellent cyclic stability. As the positive electrode material for ASC, it exhibits extremely high capacitance retention and good charge-discharge performance.