Hazel shell-based biomass-derived carbon modified diaphragm for high-performance lithium-sulfur batteries

Lithium-sulfur battery has become one of the most attractive power battery systems in the future because of their high specific energy, high energy density, good safety, green environmental protection, low cost, and so on. However, due to the "shuttle effect" caused by its polysulfide discharge product, the lithium-sulfur battery's cycle performance is poor, limiting the rapid development of lithium-sulfur batteries. In this paper, oxygen-doped hazel shell-graded porous derivative carbon with a high specific surface area was prepared by a simple template-free method and used as the functional layer of the diaphragm. Oxygen self-doping is beneficial to forming oxygen-containing functional groups on the surface, which can realize the chemical adsorption of polysulfides. The multi-stage pore structure enhances the physical confinement effect of carbon materials on polysulfides. In addition, it is found that the initial capacity of the modified diaphragm can reach 1318.8 mAh g-1 at 0.2C current density. And the initial capacity can still reach 1035.6 mAh g-1 even at 1 C current density, after 500 cycles, the capacity retention rate is 60.9%, which has good rate performance and cycle stability.