Sustainable “Sweet and Salty” Synthesis of Hierarchical Porous Carbon for Lithium–Sulfur Batteries

State-of-the-art Li–S batteries (LSBs) still suffer from a series of technical issues, including rapid capacity fading, due to polysulfide dissolution and shuttling, low active material loading in the cathode, and sluggish reaction kinetics. These challenges can be combatted through the application of efficient sulfur hosts that provide ample void structures, maintain electronic and ionic pathways, and confine soluble polysulfides within the cathode. This work uses sustainable glucose and sodium chloride as the precursors in a “sweet and salty” synthesis method to produce hierarchical porous carbon as the sulfur host for LSB cathodes. The as-prepared hierarchical porous carbon host (HPCH) is shown to have an exceptionally large specific surface area of 1540 m2 g–1 with a favorable pore size distribution due to the unique solvent/porogen system employed during synthesis. The porous matrix can adsorb the polysulfides at the cathode with the hydroxyl and carbonyl groups distributed on the HPCH surface. Systematic electrochemical investigation reveals that the HPCH also possesses both high ionic and electronic conductivity, which allows a reversible capacity of nearly 500 mA h·g–1 to be obtained after 500 cycles at 0.5 C and enhanced performance at high C rates. This work suggests that the as-prepared HPCH could be an excellent material to host other soluble electrode materials in electrochemical storage devices.