Hybrid Li/S Battery Based on Dimethyl Trisulfide and Sulfurized Poly(acrylonitrile)

Abstract Lithium–sulfur (Li/S) batteries are among the most promising next‐generation energy storage systems because of their high theoretical specific energy of ≈2600 Wh kg⁻¹. However, conventional Li/S batteries require high amounts of redox‐inactive liquid electrolytes, which do not contribute to cell capacity. Thus, the practical specific energy of Li/S batteries is often relatively poor (<500 Wh kg⁻¹) and barely competitive with Li‐ion batteries. Herein, a new hybrid Li/S battery that contains both a liquid and a solid cathode, i.e., dimethyl trisulfide (DMTS) and fibrous sulfurized poly(acrylonitrile) (SPAN) as active materials is presented. These Li/DMTS/SPAN cells exhibit high capacity (formally up to 7100 mA h g_{sulfur of cathode}⁻¹), high areal capacity up to 4.3 mA h cm⁻², high rate capability up to 8 C, and excellent cycle stability (>700 cycles). In addition, both the working and aging mechanism are elucidated by NMR, Raman, X‐ray photoelectron and electronic impedance spectroscopy, X‐ray powder diffraction, cyclic voltammetry, and postmortem analysis.