Tetrabutylammonium-Intercalated 1T-MoS_2 Nanosheets with Expanded Interlayer Spacing Vertically Coupled on 2D Delaminated MXene for High-Performance Lithium-Ion Capacitors

摘要

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.