Adsorption of LIBs Thermal Runaway Gases on TM-Decorated HfS₂ Surface: A DFT Study

With the wide application of lithium-ion batteries (LIBs) in different fields, safety accidents occur frequently. Therefore, it is necessary to monitor the thermal runaway gas for an early warning. In this article, the adsorption properties of the characteristic gases of LIBs thermal runaway gases are studied by density functional theory (DFT). The adsorption structure of TM (Co/Rh/Ir)-decorated HfS₂ (TM@HfS₂) is established, and its adsorption properties for C₂H₄, CH₄, and CO are studied. The adsorption energy, charge transfer, band, DOS, charge difference density, work function, and recovery time are discussed in detail. The results show that Ir@HfS₂ has the strongest adsorption performance for C₂H₄ and CO, so C₂H₄ and CO can be stably adsorbed on the surface of the Ir@HfS₂ monolayer. The adsorption energy of CH₄ on Co@HfS₂ is stronger than those of Rh@HfS₂ and Ir@HfS₂, but the adsorption energy is still very small. By applying biaxial strain to Co@HfS₂, we found that the adsorption energy increases with the increase in negative strain. This study provides a theoretical basis for the regulation of the adsorption properties of HfS₂ by different transition metals.