Simple and Scalable Synthesis of Sulfurized Polyacrylonitrile Cathodes for Li/s Batteries

Abstract

Li/S battery has high potential for large scale batteries due to their high theoretical energy density. For high practical energy density of Li/S batteries, a method for synthesizing a new electrode structure should be developed. We demonstrate the development of low-cost Li/S batteries via the simple synthesis of sulfurized polyacrylonitrile (S-PAN) using a glass casting and heating method. The optimum conditions for electrode synthesis were determined using various precursor ratios. Structural characterization of the S-PAN electrodes was performed through scanning electron microscope, X-ray diffractometer, and elemental analysis. At the molecular scale, the S-PAN particles are connected to each other through π-conjugated structures. Furthermore, the electrodes possess high internal porosity, which improves the Li+ ion mobility through enhanced electrolyte uptake. The S-PAN electrodes synthesized using an S:PAN ratio of 5:1 exhibited the best practical capacity after 30 cycles (327 mAh g−1-electrode, 1065 mAh g−1-S). Significantly, the impressive capacity and cyclability of the S-PAN cathode are achieved without using a binder or conducting agents. Therefore, glass-cast S-PAN represents a simple, low-cost approach for synthesizing Li/S batteries with improved capacity.