In Situ Construction of Accordion-like Nano MoS2@Multilayered Mo2CTx Hybrid Framework toward Sodium Ion Capacitors

Unique merits, including a typical lamellar structure, large crystal plane spacing, and high theoretical capacity, make MoS2 widely utilized for sodium ion capacitors (SICs) as a competitive anode. However, some issues such as easy layer agglomeration, poor conductivity, and serious volume expansion greatly limit its practical applications for SICs. For this, herein, we smartly fabricate an accordion-like MoS2/Mo2CTx heterostructure composite, where nanoscale MoS2 is in situ formed on multilayered Mo2CTx via a simple vapor vulcanization avenue. The unique accordion-like heterostructure framework endows the MoS2/Mo2CTx hybrid with robust structural stability, convenient Na+ transport, enhanced electronic conductivity, and nanodimension-induced high electroactivity. When evaluated for SICs, the hybrid MoS2/Mo2CTx anode exhibits remarkable rate properties and electrochemical stability, i.e., a competitive capacity of 210.2 mAh g–1 after 1000 cycles at 1.0 A g–1. Furthermore, the MoS2/Mo2CTx-assembled SICs provide a large energy density of 23.3 Wh kg–1 for the case of 3500 kW kg–1, as well as a superb capacitance retention of 76.8% after 5000 consecutive cycles at 1 A g–1. More meaningfully, our devised strategy here holds promising potential for synthesizing other versatile functional composites toward SICs and beyond.