Redox density of states and quantum capacitance in sulfurized polyacrylonitrile

Sulfurized polyacrylonitrile (SPAN) is an interesting material that shows highly stable performance unlike elemental sulfur cathodes in Li-S batteries. Although many researchers investigated SPAN, its exact structure and thus the fundamental redox reactions are not yet fully known. We used a comprehensive array of tools such as in-situ Raman, x-ray photoemission (XPS), and electrochemical capacitive spectroscopy (ECS) to experimentally investigate the electrochemistry of SPAN. Based on these results, this talk will present the use of ECS to derive redox density of states, understand the effects of quantum capacitance, and identify the molecular mechanisms in SPAN.