From one-dimensional to three-dimensional, the criss-crossed fiber materials forge high-performance lithium-sulfur batteries

Lithium-sulfur batteries are considered the preferred system for high-performance batteries due to their high theoretical energy capacity density, environmental friendliness, and wide range of available sources of the active substance sulfur. However, the challenges inherent in lithium-sulfur batteries, such as polysulfide shuttling, sulfur insulation, lithium dendrites, and volume changes, have greatly impeded their progress towards commercialization. Fortunately, the inherent flexibility, lightweight nature, expansive surface area, and cost-effectiveness of fiber materials offer significant potential to tackle these challenges. In cathode, the layered structure formed by stacking fiber materials can effectively inhibit polysulfides and mitigate volume changes, thereby maintaining the stability of the cathode. In separator, fibers can help distribute lithium ions evenly, which can prevent the formation of dendrites and reduce the risk of puncture. In anode, the three-dimensional structure of the fiber materials can effectively guide the uniform distribution of lithium and also enhance the mechanical properties. The fiber-based interlayer is also present to inhibit the shuttling of polysulfides or guide the distribution of lithium ions. In this paper, fibers are categorized based on their conductivity, and the paper elaborates in detail on the effects of fiber types (such as carbon, metal, aramid, and glass fibers), structural designs (porous, hollow, core–shell, etc.), and modifications (elemental doping, metal-compound modification, and synergistic modification by elemental doping and metal compounds) on the electrochemical performance of batteries, as well as the mechanism of their effects in various position. Finally, an outlook on the evolution direction and existing troubles of flexible batteries are also given.