Facile fabrication of novel Ti3C2Tx-supported fallen leaf-like Bi2S3 nanopieces by a combined local-repulsion and macroscopic attraction strategy with enhanced symmetrical supercapacitor performance

Abstract

Hybrid electrode materials with superior electrochemical performance are highly desired to fulfil the ever-increasing energy-density demands of supercapacitors. Herein, a facile and efficient ion-attraction strategy is demonstrated for the construction of a uniform heterostructure of Bi2S3/Ti3C2Tx (BSTC) nanocomposites, in which fallen leaf-like Bi2S3 nanopieces are firstly planted on the surface of Ti3C2Tx due to the local-repulsion of Ti atoms and the macroscopic attraction of functional groups (OH/O/F) to Bi3+. The DFT calculation was conducted to explain the morphology transformation mechanism from nanoparticles to nanopieces and the enhancement of the electrical conductivity of Bi2S3 is due to the incorporation of Ti3C2Tx. When used as a supercapacitor electrode, the BSTC-29 (Ti3C2Tx content: 29 wt.%) nanocomposite exhibits a superior electrochemical performance with an enhanced capacity of 615 C g-1 at a high discharge current density of 3 A g-1, and a high capacitance retention up to 91% is also obtained due to the enhanced structural stability. Furthermore, the assembled symmetrical supercapacitor exhibits both a high energy density of 27.6 Wh kg-1 and a power density of 24.3 kW kg-1, respectively, surpassing those of Bi2S3 and Ti3C2Tx in this study and many other related composites in literature. This study presents a new promising strategy for the synthesis of high-performance supercapacitor electrode materials.