Enabling effective polysulfide trapping and high sulfur loading via a pyrrole modified graphene foam host for advanced lithium-sulfur batteries

Traditional Li-ion batteries are facing problems due to the intrinsic limitation of their low energy density. As one type of promising Li battery, lithium-sulfur (Li-S) batteries have an advantage of high theoretical energy density (2600 W h kg⁻¹). Nevertheless, the notorious polysulfide shuttle and low sulfur loading are the main obstacles to widespread practical utilization of Li-S batteries. To tackle these issues, we design and construct a pyrrole modified graphene aerogel foam (Py-GF) by a simple hydrothermal and freeze drying method as the sulfur host, where pyrrole provides strong chemical bonding for polysulfide anchoring and graphene aerogel foam serves as a matrix to enhance the conductivity as well as increase the sulfur loading of the cathode simultaneously. The Py-GF@S cathode, with a high sulfur loading of about 6.2 mg cm⁻², displays an improved initial specific capacity (1220 mA h g⁻¹ at 0.2C and 985.8 mA h g⁻¹ at 0.5C) and cycle stability (capacity retention of 81% after 100 cycles at 0.5C). We anticipate that the work described here will be helpful to develop Li-S batteries that meet the requirements of practical applications.