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Simultaneously achieving a high conductivity and a good volume-change accommodation for sulfur cathode in lithium‑sulfur batteries is highly required. Herein, we present a unique porous sulfur composite consisting of a porous sulfur particle coating with conductive hydrogel polypyrrole, which is prepared through a templated method. The pores inside the sulfur particles offer a good buffering space for the volume expansion of sulfur upon lithiation; while the external polypyrrole coating improves the conductivity and suppress the transfer of polysulfides. The porous sulfur@polypyrrole composite exhibits a capacity of about 900 mAh g−1 after cycling for 100 times at 0.12 C, along with a good Coulombic efficiency around 99.9%, which is much better than the polypyrrole-coated non-porous sulfur particles and pure sulfur particles. When cycled for 500 times, the capacity fading rate is as low as 0.09% per cycle. After three rounds of rate-performance measurements, the capacity retention of the sulfur@polypyrrole at different rates remain above 97%. The density functional theory calculations and electrochemical impedance spectra demonstrate a polysulfide-adsorptive and a stable electric transportation surface of the sulfur@polypyrrole composite, respectively. Unlabelled Image • A novel porous sulfur@hydrogel composite cathode is reported. • The Li-S batteries exhibit high electrochemical performance. • The cathodes enable accommodable volume-change and improved conductivity. • High proportion of capacitive contribution in overall capacity is achievable. • Density functional theory calculations demonstrate polysulfides adsorption. [ABSTRACT FROM AUTHOR]

• A novel polysulfides-immobilized composite is presented for Li-S battery. • The TiO 2 @PANI@S composite exhibits a high electrochemical performance. • Strong adsorption between the composite and polysulfides is presented. • Enhanced electron transfer and ion diffusion are achievable. Li-S batteries are promising new energy-storage systems owing to their high theoretical energy density. However, the volume-change and poor conductivity of S, and shuttle effect severely restrict applications. Here, we present a novel semispherical composite consisting of sulfur and polyaniline (PANI) hydrogel coating on a bowl-shaped hollow TiO 2. The TiO 2 @PANI@S composites show an excellent performance with a high capacity of 1058 mAh g−1 after 200 cycles at 0.2 C, and a stable Columbic efficiency of 99.8%. The composites also possess a recoverable rate-performance under repeated tests. The Li+ ion diffusion co-efficiency is studied, which indicates that the semispherical composite enables a rapid Li+ ion transportation. In addition, the density functional theory calculations confirm a strong adsorption of TiO 2 towards polysulfides including for Li 2 S 4 , Li 2 S 6 , and Li 2 S 8 , which efficiently suppress the shuttle effect. [ABSTRACT FROM AUTHOR]