A lithium-sulfur full cell with ultralong cycle life: influence of cathode structure and polysulfide additiveElectronic supplementary information (ESI) available. See DOI: 10.1039/c4ta06748g

• Main Authors: Thieme, Sören, Brückner, Jan, Meier, Andreas, Bauer, Ingolf, Gruber, Katharina, Kaspar, Jörg, Helmer, Alexandra, Althues, Holger, Schmuck, Martin, Kaskel, Stefan
• Format: Journal Article
• Language: English
• Published: 03.02.2015
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c4ta06748g

Lithium-sulfur batteries are highly attractive energy storage systems, but suffer from structural anode and cathode degradation, capacity fade and fast cell failure (dry out). To address these issues, a carbide-derived carbon (DUT-107) featuring a high surface area (2088 m 2 g −1 ), high total pore volume (3.17 cm 3 g −1 ) and hierarchical micro-, meso- and macropore structure is applied as a rigid scaffold for sulfur infiltration. The DUT-107/S cathodes combine excellent mechanical stability and high initial capacities (1098-1208 mA h g S −1 ) with high sulfur content (69.7 wt% per total electrode) and loading (2.3-2.9 mg S cm −2 ). Derived from the effect of the electrolyte-to-sulfur ratio on capacity retention and cyclability, conducting salt is substituted by polysulfide additive for reduced polysulfide leakage and capacity stabilization. Moreover, in a full cell model system using a prelithiated hard carbon anode, the performance of DUT-107/S cathodes is demonstrated over 4100 cycles (final capacity of 422 mA h g S −1 ) with a very low capacity decay of 0.0118% per cycle. Application of PS additive further boosts the performance (final capacity of 554 mA h g S −1 ), although a slightly higher decay of 0.0125% per cycle is observed. A carbide-derived carbon with hierarchical pore structure, large pore volume and high surface area was applied as a rigid, conductive scaffold for sulfur conversion. Full cell tests revealed high performance and reversible cycling over 4100 cycles.