Flexible and free-standing bacterial cellulose derived cathode host and separator for lithium-sulfur batteries

This study demonstrates flexible, ultra-high rate, and long cycle life lithium-sulfur batteries using bacterial cellulose (BC) derived cathode host as well as separator. The work also includes a new strategy to use active sulfur in the form of catholyte added directly to the electrolyte for improved sulfur utilization. The fabricated Li-S cell with carbonized bacterial cellulose (CBC) as a cathode host and BC as a separator (CBC@BC) delivers an impressive capacity of 740 mAh g-1 at 1C. It retains a capacity of 310 mAh g-1 even at an ultra-high rate of 4C. To have commercial adoption of CBC@BC, we tested Li-S cells with a high areal loading of 5 mg cm-2. The cell shows promising electrochemical performance for 500 cycles with a capacity retention of 82 %. Furthermore, first-principle calculations are performed to understand the interaction of soluble lithium-polysulfides with bacterial cellulose-derived material.

Automated summary

This study demonstrates the use of bacterial cellulose as a cathode host and separator in flexible, ultra-high rate, and long cycle life lithium-sulfur batteries. The addition of active sulfur directly to the electrolyte improves sulfur utilization. The study also investigates the interaction between bacterial cellulose-derived material and soluble lithium-polysulfides.