First-Principles Study on the Adsorption and Dissociation of Impurities on Copper Current Collector in Electrolyte...

The copper current collector is an important component for lithium-ion batteries and its stability in electrolyte impacts their performance. The decomposition of LiPF₆ in the electrolyte of lithium-ion batteries produces the reactive PF₆, which reacts with the residual water and generates HF. In this paper, the adsorption and dissociation of H₂O, HF, and PF₅ on the Cu(111) surface were studied using a first-principles method based on the density functional theory. The stable configurations of HF, H₂O, and PF₅ adsorbed on Cu(111) and the geometric parameters of the admolecules were confirmed after structure optimization. The results showed that PF₅ can promote the dissociation reaction of HF. Meanwhile, PF₅ also promoted the physical adsorption of H₂O on the Cu(111) surface. The CuF₂ molecule was identified by determining the bond length and the bond angle of the reaction product. The energy barriers of HF dissociation on clean and O-atom-preadsorbed Cu(111) surfaces revealed that the preadsorbed O atom can promote the dissociation of HF significantly.