Easily Accessible, Textile Fiber-Based Sulfurized Poly(acrylonitrile) as Li/S Cathode Material: Correlating Electrochemical Performance with Morphology and Structure

Lithium-sulfur (Li/S) technology holds great promise for efficient, safe, and economic next-generation batteries. However, commercialization is limited by some issues, which are related to the fast degradation of Li/S cells and poor rate capability. Existing strategies addressing these issues are often unsuitable for commercialization because of their complexity and lack of scalability. This Letter presents a simple, cheap, and scalable synthesis of a sulfur-based cathode material from commercially available poly(methyl methacrylate)/poly(acrylonitrile) (PMMA/PAN) fibers. Thermal conversion of PMMA/PAN fibers with elemental sulfur yields sulfurized poly(acrylonitrile) (SPAN) with up to 46 wt % covalently bound sulfur. The fibrous morphology with cylindrical macropores helps to form electronic conduction networks in the cathode and provides directed diffusion pathways for ions. Consequently, these Li/SPAN cells show low internal resistances, high initial capacities up to 1672 mAh center dot g(sulfur)(-1), high rate capabilities up to 8C, and excellent cycle stabilities over 1200 cycles. In addition, structure and postmortem analysis allow the correlation of electrochemical performance with SPAN's chemical structure. [GRAPHICS]