A Scaled‐Up Lithium (Ion)‐Sulfur Battery: Newly Faced Problems and Solutions

Lithium‐sulfur (Li‐S) batteries are extensively explored due to their substantially higher theoretical energy density compared to any commercially available rechargeable batteries. Highly innovative efforts are invested to demonstrate promising Li‐S cells at laboratory scales. In order to promote this battery technology further, it is important to develop and test sulfur cathodes with practically high loading per unit area. The work described herein is devoted to long‐term testing of Li‐S and Si‐Li‐S cells comprising electrodes with high loading of the active mass, in pouch cells. This study investigates composite cathodes in which sulfur is embedded in matrices of multiwall carbon nanotubes and composite anodes based on prelithiated Si/SiOx nano‐spheres. These full‐cells exhibit stable cycling performance for more than 400 cycles, substantially more than equivalent cells utilizing metallic lithium anodes, which suffer from dendritic Li growth. The use of pouch cells, high cathodes' loading, and relatively high charge exchange per unit area during each cycle, emphasize the limitation of Li metal anodes in rechargeable batteries and promote development of Si‐Li‐S batteries for prolonged cycle life. Scaled‐up Li‐S pouch cells with Si anodes are evaluated in order to overcome the technical problems associated the use of metallic lithium anodes. Pouch cells (3 by 5 cm) consisting of dual‐side multiwall carbon nanotube‐S nano‐composite cathodes and prelithiated carbon coated‐Si/SiOx composite anodes (Si‐Li‐S pouch cells) show high capacity and relatively stable cycling performance during hundreds of cycles at high sulfur loading of 2.9 mg cm−2.