Single-atom catalysts supported on graphene/electride heterostructures for the enhanced sulfur reduction reaction in lithium-sulfur batteries

Single-atom catalysts (SACs) hold great promise in addressing the sluggish kinetics of the sulfur reduction reaction (SRR) in lithium-sulfur (Li-S) batteries for their unique catalytic activity and maximum atom efficiency. While these SACs must be dispersed on solid substrates, the underlying support is usually limited to carbon materials that have a poor ability to modulate the coordination environment and electronic structures of single atoms, and consequently their catalytic activity toward the SRR is restricted. Here we propose two-dimensional (2D) graphene/electride heterostructures as substrates to enhance the catalytic activities of SACs for Li-S batteries. 2D electrides featuring the anionic electron gas on their surface enable efficient electron transfer to SACs, which alters their electronic structures, resulting in the shifts of the d orbital and Fermi levels. This unique electronic structure decreases the filling of antibonding states such that the bonding with adsorbates at active sites is enhanced. We demonstrate the enhanced catalytic performance of SACs in terms of the Gibbs free energy of SRR and Li2S dissociation. In addition, a universal descriptor for the rapid screening of SACs is established by a linear regression fitting method. This work provides a new design strategy to modulate SAC activity through electrides for Li-S batteries. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.