Synergistically Enhanced Polysulfide Chemisorption Using a Flexible Hybrid Separator with N and S Dual-Doped Mesoporous Carbon Coating for Advanced Lithium?Sulfur Batteries

JUAN BALACH; HARISH KUMAR SINGH; SELINA GOMOLL; TONY JAUMANN; MARKUS KLOSE; STEFFEN OSWALD; MANUEL RICHTER; JÜRGEN ECKERT; LARS GIEBELER

ACS APPLIED MATERIALS & INTERFACES

AMER CHEMICAL SOC

Lugar: Washington; Año: 2016 vol. 8 p. 14586 - 14595

1944-8244

Because of the outstanding high theoretical specific energy density of 2600 Wh kg?1, the lithium?sulfur (Li?S) battery is regarded as a promising candidate for post lithium-ion battery systems eligible to meet the forthcoming market requirements. However, its commercialization on large scale is thwarted by fast capacity fading caused by the Achilles? heel of Li?S systems: the polysulfide shuttle. Here, we merge the physical features of carbon-coated separators and the unique chemical properties of N and S codoped mesoporous carbon to create a functional hybrid separator with superior polysulfide affinity and electrochemical benefits. DFT calculations revealed that carbon materials with N and S codoping possess a strong binding energy to high-order polysulfide species, which is essential to keep the active material in the cathode side. As a result of the synergistic effect of N, S dual-doping, an advanced Li?S cell with high specific capacity and ultralow capacity degradation of 0.041% per cycle is achieved. Pushing our simple-designed and scalable cathode to a highly increased sulfur loading of 5.4 mg cm?2, the Li?S cell with the functional hybrid separator can deliver a remarkable areal capacity of 5.9 mAh cm?2, which is highly favorable for practical applications.