Molecular dynamics simulation study on the interaction mechanisms of leaching solutions and LiCoO2 surface

The mechanism of interaction between H2SO4 + H2O2 solution and LiCoO2 surface were studied by molecular dynamics（MD）simulation. The impact of H2SO4 concentration, H2O2 dosage, and temperature on the alterations in the molecular distribution characteristics in the leaching solution was revealed by analyzing the diffusion coefficients, radial distribution function (RDF), and interaction energies from a molecular perspective. The simulation results show that the diffusion coefficients of H2O, H2O2, and SO2-4 increase and subsequently decrease with increasing H2SO4 concentration and H2O2 dosage, and they increase with increasing temperature. The radial distribution function shows a strong spatial correlation between the H2O2 molecules and the LiCoO2 surface at 1.125 Å, and the highest peak value is 31.21 with 3 M H2SO4, 12 vol% H2O2, and temperature of 363 K. The non-bonding interaction energy between leaching solution and LiCoO2 surface consists of electrostatic force, and the order of the influencing strength of these three factors on the interaction energy is as follows: H2O2 dosage > temperature > H2SO4 concentration. Additionally, the simulation results were validated through single factor leaching experiments. This study provided a molecular-level understanding of the leaching mechanisms of spent LiCoO2 batteries.