First-Principles Study on the Adsorption and Dissociation of Impurities on Copper Current Collector in Electrolyte for Lithium-Ion Batteries

The copper current collector is an important component for lithium-ion batteries and its stability in electrolyte impacts their performance. The decomposition of LiPF(6) in the electrolyte of lithium-ion batteries produces the reactive PF(6), which reacts with the residual water and generates HF. In this paper, the adsorption and dissociation of H(2)O, HF, and PF(5) on the Cu(111) surface were studied using a first-principles method based on the density functional theory. The stable configurations of HF, H(2)O, and PF(5) adsorbed on Cu(111) and the geometric parameters of the admolecules were confirmed after structure optimization. The results showed that PF(5) can promote the dissociation reaction of HF. Meanwhile, PF(5) also promoted the physical adsorption of H(2)O on the Cu(111) surface. The CuF(2) 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.