Heteronuclear Binary-Atom-Controlled Cobalt-Based Catalyst for Lithium-Sulfur Batteries

This study successfully designed and synthesized a series of cobalt-based catalysts (CoB, CoTiB, and CoCrB) via an ionic modulation strategy, systematically investigating the influence of different metal ions on the catalytic performance of lithium–sulfur batteries and the underlying mechanisms. A low-energy solution-chemical method under alkaline conditions was employed to introduce B, Ti, and Cr elements, using branched-chain cobalt acetate as the cobalt source to construct amorphous/microcrystalline boride materials with high specific surface area and abundant active sites. Structural characterization and theoretical calculations reveal that the introduction of Cr effectively modulates the electronic structure of the material, enhancing its adsorption and catalytic conversion capability toward polysulfides. Electrochemical tests demonstrate that CoCrB exhibits superior reaction kinetics, including low charge-transfer resistance, high polysulfide conversion efficiency, and rapid lithium-ion migration, which is primarily attributed to the orbital-electron synergy between Cr ³⁺ and Co ²⁺ . In contrast, CoTiB achieves a better balance between catalytic activity and structural stability, showing excellent reaction reversibility and cycling stability. Long-term cycling and rate performance tests further confirm that CoCrB maintains high capacity retention after 500 cycles at 2 C and delivers favorable rate capability across various current densities. This work clarifies the synergistic enhancement mechanism of heteronuclear diatomic regulation on cobalt-based catalysts, providing new insights and an experimental basis for the design of efficient and stable Li–S battery catalysts through electronic structure modulation.