Technologies for high-energy and long cycle life lithium-sulfur pouch-cell batteries

The current lithium-ion battery technol. is limited to about 250 Wh kg♂1. In contrast the lithium-sulfur battery is expected to achieve more than 400 Wh kg♂1 on cell level. To date the biggest drawback of lithium- sulfur is its limited cycle stability of less than 200 cycles. Further, high energy densities can only be achieved if no excess of lithium and electrolyte is used and the areal loading of sulfur is high. Here we demonstrate how the cycle stability can be extended to 1000 cycles using alternative silicon-carbon and all-carbon anodes instead of metallic lithium. We also present a dry-processing technol. for the sulfur cathode prepn. Besides no drying step and no toxic solvents, our process enables also twice the areal capacity (4-5 mAli cm2) of slurry based technologies. In addn. we give results on the cycle stability and energy d. of our lithium-sulfur pouch- cells (2.5+ Ah).