Molten Salt Electrochemical Modulation of Iron–Carbon–Nitrogen for Lithium–Sulfur Batteries

Abstract Sulfur hosts with rationally designed chemistry to confine and convert lithium polysulfides are of prime importance for high‐performance lithium–sulfur batteries. A molten salt electrochemical modulation of iron–carbon–nitrogen is herein demonstrated as formation of hollow nitrogen‐doped carbon with grafted Fe 3 C nanoparticles (Fe 3 C@C@Fe 3 C), which is rationalized as an excellent sulfur host for lithium‐sulfur batteries. Fe 3 C over nitrogen‐doped carbon contributes to enhanced adsorption and catalytic conversion of lithium polysulfides. The sulfur‐loaded Fe 3 C@C@Fe 3 C electrodes hence show a high capacity, good cyclic stability, and enhanced rate performance. This work highlights the unique chemistry of metal carbides on facilitating adsorption–conversion process of lithium polysulfides, and also extends the scope of molten salt electrolysis to elaboration of energy materials.