Tetrabutylammonium‐Intercalated 1T‐MoS2 Nanosheets with Expanded Interlayer Spacing Vertically Coupled on 2D Delaminated MXene for High‐Performance Lithium‐Ion Capacitors

Abstract 2D 1T phase MoS2 (1T‐MoS2) nanosheet with metallic conductivity and expanded interlayer spacing is considered as a highly potential lithium storage electrode material but remains thermodynamic instability in aqueous media, seriously hindering the electrochemical performance. Herein, a versatile strategy is proposed for the preparation of thermodynamically stable 1T‐MoS2/MXene heterostructures with the aid of delaminated Ti3C2Tx MXene (d‐Ti3C2Tx) dispersion containing tetrabutylammonium hydroxide. The 2D d‐Ti3C2Tx provides more uniform nucleation sites for MoS2, and the TBA+ ions can intercalate into MoS2 to induce the phase conversion from semiconducting 2H to 1T. Moreover, the electrochemical advantages of 1T‐MoS2 and d‐Ti3C2Tx can be united by the construction of a well‐organized heterostructure. Outstanding rate performance is realized because of extra‐large interlayer space of 1T MoS2 with TBA+ intercalation and decreased energy barrier for fast Li+ diffusion. Subsequently, a lithium‐ion capacitor (LIC) is assembled based on 1T‐MoS2/d‐Ti3C2Tx as anode and hierarchically porous graphene nanocomposite with micro/mesoporous structure as a cathode. The LIC exhibits a large energy density up to 188 Wh kg−1, an ultra‐high power density of 13 kW kg−1, together with remarkable capacity retention of 83% after 5000 cycles. This study demonstrates the great promise of 1T‐MoS2/d‐Ti3C2Tx heterostructures as anode for high‐performance LICs.