Bacterial Cellulose-Derived Self-Supported Carbon Electrodes for Stable Performance Metal–Sulfur Batteries: A Novel Approach toward Full-Cell Studies

Metal–sulfur batteries are the most sought next-generation energy storage devices due to their higher energy density compared to currently used lithium (Li)-ion batteries. However, their commercialization has been hampered due to the insulating nature of sulfur (S) and metal anode corrosion arising from the shuttle effect of soluble polysulfides. To overcome this, we report replacing the metal anode with a self-supported lithiated/potassiated carbon electrode to reduce the anode degradation in the full-cell assembly of metal (Li/K)–S batteries. These self-supported electrodes are also used as cathodes after being loaded with a catholyte (Li2S6/K2S6). The self-supported carbon electrodes are derived from bacterial cellulose (BC) upon controlled pyrolysis. An as-fabricated Li–S full cell delivers a capacity of 270 mAh g–1, retaining 70% of the initial capacity after a continuous 1000 cycles with an energy density of 350 W h kg–1 at 0.5C. The feasibility of the K–S full-cell configuration is also explored, delivering a capacity of 120 mAh g–1 at 0.1C. A high sulfur loading of 4.0 mg cm–2 is used to assess the commercial feasibility. Through this work, we successfully demonstrate the practical realization of metal (Li/K)–S batteries with excellent performance using sustainable and scalable biopolymer (BC)-derived carbon as a self-supported electrode.