Doped carbons for room-temperature Na–S batteries: a comprehensive review

Abstract

Despite high theoretical energy density, low cost, and abundant natural resources, the development of emerging room-temperature sodium–sulfur (Na–S) batteries is still confronting many challenges. These key issues include the insulating nature of solid sulfur, the shuttle effect of polysulfides, sluggish reaction kinetics, and sodium dendrite growth. Doped carbon materials hold multiple advantages including tunable electronic structures, abundant polar sites, high specific surface areas, and outstanding electrocatalytic activity, which make them promising for dendrite-free sodium anodes and electrochemically stable sulfur cathodes. This review systematically deciphers the research development of doped carbon materials for Na–S batteries. The electrochemical principles and core challenges of Na–S batteries are discussed first. The key roles of doping sites in Na–S electrochemistry and various typical doping configurations are then elaborated. Next, we place emphasis on the practical applications of doped carbons in Na–S batteries, including cathode hosts, separators/interlayers, and sodium anode skeletons. Finally, the challenges and future directions are summarized, aiming to guide advanced material designs for Na–S batteries.