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Promoting the reversible structural transformation and carrier migration dynamics simultaneously in a multiple ion-involved process is vital for sulfide electrode materials. Herein, TiS2 with a sulfide cluster vacancy (CV–TiS2−x) has been calculated and prepared to explore a novel strategy to improve the electrochemistry reversibility of sulfide electrodes. It is found that the cluster vacancy can serve as an effective control factor for the improvement of the Fermi level, and enhances the electrochemical stability of CV–TiS2−x in the liquid organic electrolyte system. Moreover, owing to the plentiful positively charged S-vacancies, the CV–TiS2−x samples exhibit an extended interplanar spacing and retain their structural integrity during the lithium ion insertion process. The integrated HRTEM, in situ XRD, XPS analysis and electrochemical study reveal that the cluster vacancy is not only responsible for an increase in reversible performance, but also boosting the anionic redox reaction of (S2)2− species. Therefore, the CV–TiS2−x electrode delivers a reversible capacity of 650 mA h g−1 for 300 cycles at a current density of 1C (220 mA g−1). Our study provides a novel strategy of introducing sulfur cluster vacancies to improve the electrochemical activity of TiS2, which can be applied to other sulfide electrodes.

Volume changes, polysulfide shuttle effects, and low Li-ion/electronic conductivity of sulfide electrodes limit their application in Li-ion batteries with high-energy density. Here, micron FeS2 particles with bifunctional carbon nanotubes (FeS2@B–CNTs) including CNT internal conductive networks and external protective cages were prepared by a one-step solvothermal method. The internal CNTs anchor FeS2via chemical binding, which much more effectively inhibited the shuttle effect than physical confinement alone. Meanwhile, reticular CNT cages were generated on the surface of the composite FeS2 micron particles, buffering volumetric changes during cycling and further restraining the shuttle of polysulfides. Additionally, a three-dimensional CNT framework offered a primarily continuous charge transfer pathway. The FeS2@B–CNTs electrode had a high initial coulombic efficiency of 91.3% and delivered a capacity of 698 mA h g−1 over 500 cycles at 1000 mA g−1. The Li-ion diffusion coefficient is two orders of magnitude higher than those of previous reports, which improved the rate performance of the FeS2@B–CNTs electrode. These studies on micron FeS2 spheres shed light on the design strategies for the application of sulfide electrodes.