Hierarchically porous carbon as a sulfur host and an interlayer for high-performance lithium-sulfur batteries

Lithium–sulfur (Li–S) batteries are considered promising next-generation energy storage systems due to their high theoretical energy density and use of cost-effective active material. However, their practical applications are impeded by intrinsic issues such as sulfur's low electrical conductivity, severe volume change during cycling, and the polysulfide shuttle effect. In this study, hierarchically porous carbon (HPC) materials with interconnected meso- and macropores are developed and employed both as a sulfur host and a functional interlayer in Li–S batteries. Among the samples, HPC-3 exhibits a significantly high pore volume (4.16 cm 3 g −1 ) and large surface area (1918.3 m 2 g −1 ), enabling sulfur loadings of ≥80 wt% while retaining sufficient porosity for electrolyte access and volume buffering of sulfur during cycling. In Li–S cells, the S@HPC-3 cathode with uniform sulfur distribution shows enhanced redox kinetics, and effective polysulfide immobilization. Moreover, the application of an HPC-3 interlayer further inhibits polysulfide diffusion and reduces the internal resistance of the cell. The dual use of HPC-3 leads to synergistic improvements in cycling stability—particularly under high sulfur loading—and rate capability. This work demonstrates the importance of structural engineering of porous carbon materials and provides a comprehensive strategy for advancing high-performance Li–S batteries. • Interconnected meso/macroporous hierarchically porous carbons (HPCs) were developed. • The HPCs have large pore volumes that accommodate high sulfur loadings (≥80 wt%). • Well-developed pores in HPC-3 adsorb polysulfides, suppressing the shuttle effect. • Dual use of HPC-3 as host and interlayer provides synergistic cycling stability.