Porous Ti₄O₇ Particles with Interconnected-Pore Structure as a High-Efficiency Polysulfide Mediator for Lithium–Sulfur Batteries

Multifunctional Ti₄O₇ particles with interconnected-pore structure are designed and synthesized using porous poly(styrene-b-2-vinylpyridine) particles as a template. The particles can work efficiently as a sulfur-host material for lithium–sulfur batteries. Specifically, the well-defined porous Ti₄O₇ particles exhibit interconnected pores in the interior and have a high-surface area of 592 m² g⁻¹; this shows the advantage of mesopores for encapsulating of sulfur and provides a polar surface for chemical binding with polysulfides to suppress their dissolution. Moreover, in order to improve the conductivity of the electrode, a thin layer of carbon is coated on the Ti₄O₇ surface without destroying its porous structure. The porous Ti₄O₇ and carbon-coated Ti₄O₇ particles show significantly improved electrochemical performances as cathode materials for Li–S batteries as compared with those of TiO₂ particles.