Rational Design of Metal-Doped Graphitic Materials for Enhanced Lithium-Sulfur Batteries.

Abstract

Atomically dispersed metal atoms within graphitic carbon have shown great potential in enhancing the performance of lithium-sulfur batteries (LSBs), though the fundamental principles to guide their rational design remain to be fully established. Here, we report a combined computational and experimental study demonstrating that a group of metals (Ti, V, Mo, and Nb) incorporated into graphitic carbon have promising catalytic properties due to three factors: strong binding with lithium sulfides, reduced redox overpotentials, and low kinetic barriers for Li-S bond activation. In contrast, metals such as Fe and Mn show moderate catalytic behavior, while Ni representing a third group of elements has worse performance. To validate these computational predictions, we synthesized and studied three representative metal elements─Nb, Fe, and Ni─each exhibiting distinct capabilities in binding LiPSs/Li₂S and catalyzing polysulfide conversion with varying overpotentials and kinetic barriers. Among them, Nb delivered the most exceptional performance, including superior rate capability (679.3 mA h g^-1 at 5 C), high capacity retention (837.5 mA h g^-1), and a low capacity decay rate (0.023% per cycle) after 500 cycles at 1 C. This work demonstrates an effective strategy that combines theoretical screening and experimental validation in exploring atomically dispersed metal catalysts for LSBs.