Advances in High Sulfur Loading Cathodes for Practical Lithium-Sulfur Batteries

Lithium-sulfur batteries hold great potential for next-generation energy storage systems, due to their high theoretical energy density and the natural abundance of sulfur. Although much progress has been achieved recently, the low actual energy density of Li-S batteries is still the key challenge in implementing their practical applications. Because the energy density greatly depends on the areal capacity of their sulfur cathodes, the sulfur content and sulfur loading play an important role in meeting the conditions necessary for practical applications. Therefore, escalating the areal capacity of sulfur cathodes is essential to promote Li-S technology from laboratory-scale devices to industrial (or commercial) systems. In this review, the recent progress in high sulfur loading of Li-S batteries (>4 mg cm−2) is highlighted from various aspects, including sulfur hosts, binders, separators, and interlayers. In particular, sulfur hosts derived from carbon, polymer, transition metal oxide/ sulfide, metal-organic framework, and other novel materials, which can promote high sulfur loading, are discussed in detail. Moreover, unique free-standing structures and configurational innovation of separators and interlayers are overviewed. Based on the current achievements, future efforts for developing high-loading Li-S batteries are proposed to pave the way for their commercial applications.