An integrated experimental and modeling study of the effect of solid electrolyte interphase formation and Cu dissolution on CuCo2O4-based Li-ion batteries

We develop an integrated framework of modeling and experiments to explain the capacity fade of the lithium-ion battery containing CuCo2O4 as the anode. The electrical conductivity, diffusion coefficient, and open-circuit voltage curves are measured from the fabricated electrodes, and the obtained properties are used for the input parameters of the side-reaction coupled electrochemical model. During the simulation, two scenarios of the degradation are considered: only the solid electrolyte interphase (SEI) formation, and coupled degradation of the SEI formation and the Cu dissolution/deposition. Sensitivity analysis is carried out with different SEI molar mass, SEI conductivity, and dissolution parameters, to evaluate the effect on the cell capacity fade. The simulation shows that active material dissolution in ternary metal oxide electrodes plays a critical role in capacity fading, and the interactions of SEI formation and active material dissolution determine the battery life. The experiment and simulation integrated framework developed in this study can be used to predict the capacity fade of the battery systems with conversion-based electrodes.