Analysis of the synthesis process of sulphur–poly(acrylonitrile)-based cathode materials for lithium batteries

Li/S batteries have attracted great attention in the last twenty years, as they offer the advantage of high gravimetric energy densities over the current conventional Li-ion systems. Besides elemental sulphur based composites, sulphur–poly(acrylonitrile)-based materials are promising candidates for Li/S batteries. Though the structure of the sulphur–poly(acrylonitrile)-based material is still debated, the effects of the synthesis conditions on the material structure, and thus on the electrochemical performance, are undoubted. Here the synthesis process of sulphur–poly(acrylonitrile)-based material is probed by scanning electron microscopy (SEM), infrared spectroscopy (IR) and ultraviolet visible spectroscopy (UV-vis), and the relationships among the synthesis conditions, material structures, and electrochemical behaviours are clarified. Consequently, the optimized synthesis is determined, by which the prepared sulphur–poly(acrylonitrile)-based material delivers a high initial coulombic efficiency of 85.6%, a high stable cycling capacity of over 795 mA h g−1, and high capacity retention of over 98.1% after 50 cycles.