In this work,we report a facile dealloying strategy to tailor the surface state of nanoporous TiO2 towards high-efficiency sulfur host material for lithium-sulfur(Li-S)batteries.When used as a sulfur cathode material,the oxygen-deficient TiO2-x exhibits enhanced lithium polysulfides(LiPS)adsorption and con-version kinetics that effectively tackle the shuttle effect in lithium-sulfur batteries.The excellent ability of the oxygen vacancy sites on TiO2-x surface to trap LiPS is proved by experimental observations and density functional theory(DFT)calculations.Meanwhile,it also promotes conversion kinetics of lithium polysul-fides,as verified by the asymmetric cell experiment.Accordingly,compared with the S/TiO2 cathode,the oxygen-deficient S/TiO2-x electrode exhibits preeminent rate and cycling performance in lithium-sulfur batteries:it delivers an ultra-low capacity decay of0.039％per cycle after 1000 cycles at 1 C.Tunning the surface state of metal oxides by dealloying method offers a new facile strategy to design efficient sulfur cathode materials for lithium-sulfur batteries.