Room‐Temperature Sodium–Sulfur Batteries and Beyond: Realizing Practical High Energy Systems through Anode, Cathode, and Electrolyte Engineering

Abstract The increasing energy demands of society today have led to the pursuit of alternative energy storage systems that can fulfil rigorous requirements like cost‐effectiveness and high storage capacities. Based fundamentally on earth‐abundant sodium and sulfur, room‐temperature sodium–sulfur batteries are a promising solution in applications where existing lithium‐ion technology remains less economically viable, particularly in large‐scale stationary systems such as grid‐level storage. Here, the key challenges in the field are first highlighted, followed by comprehensive analyses of accessible strategies to overcome them, starting from engineering of the anode–electrolyte interface in both liquid and solid electrolytes. Recently reported polymer and solid‐state electrolytes are also surveyed. Thereafter, the core principles guiding use‐inspired design of cathode architectures, covering the spectrum of elemental sulfur and polysulfide cathodes, to emerging host structures, and covalent composites are focused upon. Future prospects are explored, with insights into other alkali‐metal systems beyond sodium–sulfur batteries, such as the potassium–sulfur battery. Finally a conclusion is provided by outlining the research directions necessary to attain high energy sodium–sulfur devices, and potential solutions to issues concerning large‐scale production, so as to ultimately realize widespread deployment of practical energy storage systems.