Driven by increasing demand for high‐energy‐density batteries for consumer electronics and electric vehicles, substantial progress is achieved in the development of long‐life lithium–sulfur (Li–S) batteries. Less attention is given to Li–S batteries with high volume energy density, which is crucial for applications in compact space. Here, a series of elastic sandwich‐structured cathode materials consisting of alternating VS2‐attached reduced graphene oxide (rGO) sheets and active sulfur layers are reported. Due to the high polarity and conductivity of VS2, a small amount of VS2 can suppress the shuttle effect of polysulfides and improve the redox kinetics of sulfur species in the whole sulfur layer. Sandwich‐structured rGO–VS2/S composites exhibit significantly improved electrochemical performance, with high discharge capacities, low polarization, and excellent cycling stability compared with their bare rGO/S counterparts. Impressively, the tap density of rGO–VS2/S with 89 wt% sulfur loading is 1.84 g cm−3, which is almost three times higher than that of rGO/S with the same sulfur content (0.63 g cm−3), and the volumetric specific capacity of the whole cell is as high as 1182.1 mA h cm−3, comparable with the state‐of‐the‐art reported for energy storage devices, demonstrating the potential for application of these composites in long‐life and high‐energy‐density Li–S batteries.

Lithium-sulfur (Li-S) batteries have attracted considerable attentions in electronic energy storage and conversion because of their high theoretical energy density and cost effectiveness. The rapid capacity degradation, mainly caused by the notorious shuttle effect of polysulfides (PSs), remains a great challenge preventing practical application. Porous organic polymers (POPs) are one type of promising carbon materials to confine PSs within the cathode region. Here, the research progress on POPs and POPs-derived carbon materials in Li-S batteries is summarized, and the importance of pore surface chemistry in uniform distribution of sulfur and effective trapping of PSs is highlighted. POPs serve as promising sulfur host materials, interlayers, and separators in Li-S batteries. Their significance and innovation, especially new synthetic methods for promoting sulfur content, reversible capacity, Coulombic efficiency and cycling stability, have been demonstrated. The perspectives and critical challenges that need to be addressed for POPsbased Li-S batteries are also discussed. Some attractive electrode materials and concepts based on POPs have been proposed to improve energy density and electrochemical performance, which are anticipated to shed some light on future development of POPs in advanced Li-S batteries. a theoretical capacity of 3840 mA h g −1 , the conventional Li-S batteries could provide an average battery voltage of 2.2 V and a high theoretical energy density of 2570 W h kg −1 , which is 2-3 times higher than practical energy density of the commercial lithium ion batteries (LIBs). [4][5][6] Moreover, low cost, natural abundance, and environmental friendliness of sulfur endow Li-S batteries with great development potential and space compared with LIBs. Despite the overwhelming advantages, the practical application of Li-S batteries suffers from several technological obstacles, such as (i) poor electrical conductivities of sulfur and solid-state discharging products (Li 2 S 2 and Li 2 S); (ii) the dissolution of soluble lithium polysulfides (PSs) intermediates in the electrolytes and their free migration between cathode and anode, which results in notorious shuttle effect of PSs; (iii) huge volume fluctuation (≈80%) of the active materials during discharge and charge owing to large density difference between element sulfur and solid-state products. The major disadvantage is the shuttle effect of PSs among the above problems. During discharge and charge cycle, the dissolved high-order PSs generated in the cathode move toward the anode and react with lithium metal to form low-order PSs or a passive layer on the anode surface, low-order PSs diffuse back to the cathode and produce high-order PSs again. This process usually causes irreversible loss of active materials and low Coulombic efficiency, which are associated with fast capacity fading, low energy efficiency, severe self-discharge, and poor cycling stability. [1,[7][8][9][10] To address these problems, considerable efforts have been devoted to the devel...