Graphene-wrapped CNT@MoS2 hierarchical structure: synthesis, characterization and electrochemical application in supercapacitors

Abstract

Layered transition metal dichalcogenides (TMDs) have attracted widespread attention for developing electrochemical energy storage due to their unique graphite-like structure and high theoretical capacity. However, the semiconductor character of TMDs affects their electrical conductivity, causing low specific capacitance, rapid capacity fading and poor cyclic stability. Herein, a hierarchical graphene-wrapped CNT@MoS₂ (CMG) electrode material has been fabricated aiming at enhancing the conductivity and structural stability during continuous charge–discharge processes, thus improving its electrochemical properties. As a novel electrode material, the prepared CMG electrode delivers a high specific capacitance of 498 F g⁻¹ and excellent long-term cycle-life stability (only 5.7% loss of its initial capacitance after 10 000 cycles at a high current density of 5 A g⁻¹), as well as improved rate performance, indicating that such a composite material is an ideal electrode material for supercapacitors. Its outstanding electrochemical performance can be ascribed to an expanded interlayer spacing of MoS₂ and its unique hierarchical architecture. More importantly, this method can be readily extended to the construction of other TMD-based electrodes which were hampered in electrochemical applications owing to their poor electrical conductivity.