Advanced Lithium-Sulfur Batteries with Nanostructured Mesoporous Carbon-Coated Separators

JUAN BALACH; TONY JAUMANN; MARKUS KLOSE; STEFFEN OSWALD; JÜRGEN ECKERT; LARS GIEBELER

Singapur

Conferencia; 8th International Conference on Materials for Advanced Technologies (ICMAT2015); 2015

The lithium-sulfur (Li-S) battery is considered one of the most promising candidates for the next-generation of rechargeable batteries due to its high theoretical energy density of 2.6 kWh kg−1, which is up to 5 times higher than those of state-of-the-art lithium-ion batteries. Additionally, sulfur has the enormous advantages of being inexpensive, environmentally benign and naturally abundant. However, its commercialization has been hindered due to the insulating nature of sulfur and the poor cycling stability, mainly caused by the polysulfide shuttle phenomenon.In order to tackle these issues, we focus on the development of functional separators by a straightforward coating modification of a commercial polypropylene separator (Celgard® 2500) with nanostructured mesoporous carbon materials. The Li-S cells with a nanostructured mesoporous carbon-coated separator retain capacities of the order of 700 mAh g?1 after 500 cycles at 1 C, despite the use of a simple cathode mixture containing a high sulfur/non-porous carbon (Super P) ratio of 7:2. The enhanced electrochemical performance of the Li-S batteries is attributed to the unique features of the mesoporous carbon-coating, which effectively reduces the resistance of the sulfur cathode, promotions fast electron/lithium ion transport through the carbon network, successfully sequestrates, stores and maintains available the sulfur active material for further reutilization and buffers the large volume change during sulfur/Li2S conversion reaction. In our poster, the impact of the pore volume of the mesoporous carbons to trap polysulfides intermediates and the effect of such phenomenon on the electrochemical performance of Li-S batteries will be showed.