Surface‐Dependent Electrocatalytic Activity of CoSe<sub>2</sub> for Lithium Sulfur Battery
Xiaobiao Liu, Yibing Zheng, Mengjiao Zhang, Shiyang Qi, Ming Tan, Ruwei Zhao, Mingwen Zhao
Abstract
Abstract Electrocatalysts play key roles in improving the performance of lithium sulfur (Li‐S) batteries. Here, the electrocatalytic activity of different CoSe 2 surfaces for the polysulfide redox reactions in Li‐S batteries, by means of first‐principle calculations is considered. The authors demonstrate that there are obvious differences in surface energy (0.7–2.34 J m −2 ), adsorption energy for lithium polysulfides (LiPSs) (1.2–3.5 eV), Gibbs free energy of sulfur reduction reaction (SRR) (0.37–1.16 eV), and Li 2 S decomposition barrier (0.15–0.94 eV) among different CoSe 2 surfaces, and thus lead to the different electrocatalytic activity for different CoSe 2 surface. The stoichiometric CoSe 2 surface with high surface energy, such as the (001) surface, tends to have stronger adsorption energy and larger SRR Gibbs free energy for LiPSs. The surface electron states are mainly dominated by p – d hybridization orbitals and the p ‐band center is vital for the surface electrocatalytic properties. Such surface‐dependent mechanism may shed light on the design of sulfur host materials for high‐performance Li‐S batteries.