Hierarchical mesoporous heteroatom-doped carbon accelerating the adsorption and conversion of polysulfide for high performance Lithium–Sulfur batteries

Abstract

The critical problem of lithium-sulfur (Li–S) batteries is polysulfide shuttle effect and sluggish kinetics of lithium polysulfide conversion. Herein, a hierarchical mesoporous heteroatom-doped carbon (HMHC) including N, O, S has been fabricated using industrial waste bitumen as carbon source. This HMHC possesses high pore volume, excellent electronic conductivity, strong adsorption of lithium polysulfides and remarkable electrocatalytic effects. This HMHC as sulfur host efficiently suppresses polysulfide shuttle and improves the kinetics of electrochemical reaction. The resultant Li–S batteries with low electrolyte/sulfur (E/S) ratio of 8 μL mg−1 show outstanding electrochemical performance with high initial discharge specific capacity of 1100.6 mAh g−1 at 0.2 C and excellent capacity retention of 91% after 200 cycles. This study provides a facile method to fabricate hierarchical mesoporous heteroatom-doped carbon materials to tackle the problem of polysulfide shuttle in Li–S batteries.