Enhanced pseudocapacitive performance of MoS2 by introduction of both N-GQDs and HCNT for flexible supercapacitors

In this work, we report a strategy for enhancing the pseudocapacitive performance of MoS2 materials by the introduction of nitrogen-doped graphene quantum dots (N-GQDs) and helical carbon tubes (HCNT). By a simple hydrothermal process, the hybrid composite (MoS2, N-GQDs and HCNT) were coated on the carbon cloth (CC) without any binders, which can be directly used as advanced electrode material for high-performance solid-state flexible supercapacitors. In this hybrid structure, N-GQDs are inserted between the layers of MoS2 nanosheets, which induce and expose more active sites for pseudocapacitance contributions in MoS2 electrode materials. Meanwhile, HCNT acts as electrically conducting bridge for enhancing the electrical conductivity of MoS2 nanosheets and speeding up transport of electronic. As results, the hybrid composite (MoS2, N-GQDs and HCNT) show higher capacitive performance than pure MoS2. The specific capacitance of hybrid composite is high up to 3360 mF cm(-2). Further, the assembled solid-state flexible supercapacitor shows high specific capacitance of 1893 mF cm(-2), outstanding cycle life (capacitance retention of 86% after 2500 cycles), good mechanical stability and great flexibility. Our work provides a reference for the preparation of MoS2 composites with high supercapacitive performance. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

In this work, a strategy for enhancing the pseudocapacitive performance of MoS2 materials was reported by introducing nitrogen-doped graphene quantum dots (N-GQDs) and helical carbon tubes (HCNT). The hybrid composite exhibited higher capacitive performance than pure MoS2, attributed to the insertion of N-GQDs between MoS2 layers and the electrically conducting bridge provided by HCNT. The solid-state flexible supercapacitor assembled with this hybrid composite showed high specific capacitance, outstanding cycle life, good mechanical stability, and great flexibility.