Iron-Nickel Duo Boosts Lithium-Sulfur Battery Potential

Lithium-sulfur (Li-S) batteries hold immense potential for high-capacity energy storage, yet their efficiency is often hampered by sluggish chemical reactions. To address this, researchers are advancing from single-atom catalysts to dual-atom catalysts (DACs), which provide greater flexibility and improved catalytic effects. A recent study highlights siloxene, a polar two-dimensional material, as an ideal host to stabilise these bimetallic atoms during battery operation.

Using first-principles calculations—a method for modelling atomic behaviour based on quantum mechanics—the team evaluated a series of transition metals embedded in siloxene. The standout performer was an Iron-Nickel combination (FeNi-DA). This pairing exhibited superior catalytic activity for the critical sulfur reduction reaction and lithium sulfide oxidation. The secret to this enhanced performance lies in the orbital hybridisation between the iron and nickel atoms. This interaction redistributes the d-electron density, effectively optimising the electronic environment to speed up reactions.

Beyond mere reaction speed, the FeNi-DA structure demonstrates high electronic conductivity and favourable adsorption energies for polysulfides, addressing key stability issues in Li-S cells. The researchers also identified specific descriptors to efficiently screen for other high-performance catalysts in the future. This work sheds light on the activation mechanisms of dual-atom systems, providing a strategic pathway for designing superior cathodes for the next generation of batteries.