Diamondoid All-Carbon Porous Aromatic Framework Host for Lithium–Sulfur Batteries

Abstract

Lithium-sulfur batteries (LSBs) hold incredible potential as next-generation energy storage systems. However, practical applications of LSBs are significantly hindered by several critical challenges. For the first time, scalable all-carbon porous 3D polymers (3DPs) that do not contain heteroatoms or functional groups and do not require post-functionalization are investigated as hosts in lithium–sulfur batteries, demonstrating enhanced cycling stability and overall battery performance. The pyrene-containing 3DP exhibits 75% capacity retention after 600 cycles at 1 C and 52% capacity retention after 1300 cycles at 0.2 C, better than phenyl comprising 3DP. Furthermore, even at higher sulfur loading (4.1 mg cm⁻²) with an electrolyte/sulfur ratio of 5 µL mg⁻¹, pyrene 3DP displayed a high capacity of 600 mA h g⁻¹ and stable performance over 250 cycles with negligible capacity fade. The defined pore structure of 3DPs prevents the migration of polysulfides through physical confinement and the large π-clouds of 3DPs interact with the negative charge-bearing polysulfides generated in charge–discharge cycles through anion-π interaction. In this way, The design ensures that the host 3DPs interact with neutral sulfur and anionic polysulfides, resulting in an excellent performance.