1T-phase MoS2 is a promising electrode material for electrochemical energy storage due to its metallic conductivity, abundant active sites, and high theoretical capacity. However, because of the habitual conversion of metastable 1T to stable 2H phase via restacking, the poor rate capacity and cycling stability at high current densities hamper their applications. Herein, a synergetic effect of electron-injection engineering and atomic-interface engineering is employed for the formation and stabilization of defected 1T-rich MoS2 nanoflowers. The 1T-rich MoS2 and carbon monolayers are alternately intercalated with each other in the nanohybrids. The metallic 1T-phase MoS2 and conductive carbon monolayers are favorable for charge transport. The expanded interlayer spacing ensures fast electrolyte diffusion and the decrease of the ion diffusion barrier. The obtained defected 1T-rich MoS2/m-C nanoflowers exhibit high Na-storage capacity (557 mAh g-1 after 80 cycles at 0.1 A g-1), excellent rate capacity (411 mAh g-1 at 10 A g-1), and long-term cycling performance (364 mAh g-1 after 1000 cycles at 2 A g-1). Furthermore, a Na-ion full cell composed of the 1T-rich MoS2/m-C anode and Na3V2(PO4)3/C cathode maintains excellent cycling stability at 0.5 A g-1 during 400 cycles. Theoretical calculations are also performed to evaluate the phase stability, electronic conductivity, and Na+ diffusion behavior of 1T-rich MoS2/m-C. The energy storage performance demonstrates its excellent application prospects.
Keywords: 1T-phase MoS2; atomic-interface engineering; electron-injection engineering; sodium-ion batteries; sulfur vacancies.