Lithium sulfide (Li₂S) has drawn much attention owing to its super-high theoretical specific capacity and energy density, as well as its compatibility with lithium-free anode materials. However, the commercialization of Li₂S cathode is severely hindered by its poor rate capability and short cyclic life arising from its poor electrical conductivity, high activation energy barrier and shuttle effect of polysulfide intermediates. Many approaches have been reported, mainly focusing on the development of host for Li₂S cathode as well as electrolyte engineering, which have achieved great progress. This review firstly provides an in-depth discussion of the challenges encountered Li₂S cathode, subsequently discusses the host design for Li₂S cathode and electrolyte engineering, focusing on the fundamental mechanism underlying the host or electrolyte engineering for improving the reaction kinetics and interface stability. Finally, the remaining challenges and future directions of Li₂S cathode are discussed to further improve the performance of Li₂S cathode materials and promote their practical application.

Lithium-sulfur (Li-S) battery has attracted extensive attention because of its ultrahigh theoretical energy density and low cost. However, its commercialization is seriously hampered by its short cycling life, mainly due to the shuttle of soluble lithium polysulfides (LiPSs) and poor rate capability due to sluggish reaction kinetics. Although significant efforts have been devoted to solving the problems, it is still challenging to simultaneously address all the issues. Herein, titanium nitride hollow multishelled structure (TiN HoMS) sphere is designed as a multi-functional catalytic host for sulfur cathode. TiN, with good conductivity, can effectively catalyze the redox conversion of S and LiPSs, while its surficial oxidation passivation layer can strongly anchor LiPSs. Besides, HoMS enables TiN nanoparticle subunits to expose abundant active sites for anchoring and promoting conversion of LiPSs, while the multiple shells provide physical barriers to restrict the shuttle effect. In addition, HoMS can buffer the volume expansion of sulfur and shorten the charge transport pathway. As a result, the sulfur cathode based on triple-shelled TiN HoMS exhibits an initial specific capacity of 1016 mAh·g⁻¹ at a high sulfur loading of 2.8 mg·cm⁻² and maintains 823 mAh·g⁻¹ after 100 cycles. Moreover, it shows a four times higher specific capacity than the one without TiN host at 2 C.