Engineering Hollow-Structured Carbon Framework to Facilitate High-Sulfur-Content Encapsulation for Lithium-Sulfur Batteries

Abstract

Lithium-sulfur batteries (LSBs) have emerged as promising candidates for next-generation energy storage systems due to their high theoretical energy density and cost-effectiveness. However, their practical application is severely limited by the shuttle effect of lithium polysulfides (LiPSs) and the inherently low electrical conductivity of sulfur, which leads to rapid capacity fading and poor rate performance. To address these challenges, this work develops a hollow-structured graphitic nitrogen-doped porous carbon (h-GNPC) framework derived from zeolitic imidazolate framework-8 via a magnesiothermic reduction (MR) process. This method effectively tailors the pore architecture and electrical conductivity, enabling efficient sulfur encapsulation and high sulfur loading up to 90 wt.%. Compared to a carbon host treated without the MR method, the h-GNPC exhibits enhanced porosity, which can accommodate sulfur with stabilized cyclability. As a result, a coin cell with sulfur-loaded h-GNPC cathode exhibits an initial capacity of 1292.9 mAh g−1 and enhanced capacity retention of 74.9% over 500 cycles at 0.2C as well as rate performance. Notably, pouch-type cells assembled with the h-GNPC cathode demonstrate excellent scalability and cycling stability, highlighting the practical potential of this design for the commercialization of LSBs technology.