Asymmetric Electronic Configuration for Sustainable Lithium–Sulfur Batteries

Abstract

ABSTRACT Homonuclear diatomic catalysts (DACs) show potential for accelerating polysulfide conversion and suppressing the shuttle effect in Li−S batteries due to favorable energy‐level matching. However, their intrinsic symmetric electronic structure restricts intermetallic electron transfer, leading to unbalanced polysulfides adsorption−desorption and thus limited catalytic conversion. Herein, we construct an asymmetric Co homonuclear DAC via sulfur coordination (CoDAC‐S 1 N 5 ). Theoretical calculations reveal that the symmetry‐broken structure induces mild electron delocalization and charge redistribution. This electronic modulation contributes to cooperative yet differentiated roles of the two Co sites governed by their e g / t 2g ratios, with one site strengthening polysulfide anchoring while the other promotes S─S bond activation. This dual‐site synergy effectively overcomes the intrinsic trade‐off between adsorption strength and catalytic activity, leading to accelerated polysulfide conversion kinetics and improved reaction reversibility. As a result, CoDAC‐S 1 N 5 delivers outstanding cycling stability over 65 cycles in Ah‐level pouch cells and achieves an initial energy density of 567.8 Wh kg total −1 at a low electrolyte‐to‐sulfur ratio of 2.1 µL mg S −1 . This work establishes symmetry breaking as a key design principle for homonuclear DACs, providing mechanistic insights into the synergistic enhancement of catalytic activity and stability in Li−S systems.