Cathode materials for lithium-sulfur batteries based on sulfur covalently bound to a polymeric backbone

This review provides a comprehensive summary over polymeric cathode materials for lithium-sulfur batteries in which the sulfur is covalently bound to the polymer. The differences in electrochemical performance, in particular in terms of cycle stability, discharge rates, and coulombic efficiency between such materials and those in which the sulfur is physically confined inside the cathode material but not chemically bound to it are outlined. Special attention is given to the role of nitrogen-doping in the polymer in general, with a special emphasis on sulfurated poly(acrylonitrile) - (PAN) derived materials, referred to as SPAN as well as related materials and the structural features relevant to electrochemistry therein. The summary and interpretation of data provided here clearly outline the next steps in future developments in cathode materials for high-energy metal-sulfur batteries.