A new strategy for semi quantitative analysis of pore structure for lithium-ion battery electrodes

The Lithium ions diffusion dynamic, electrons transfer and the growth of the solid electrolyte interfaces are in close relation to the pore structure of the anodes. The widely used mercury intrusion porosimetry suffers from serious severe reaction with the copper and aluminum substrate, and unable to provide the pore structure evolution in the cross-section direction of the electrode. And the X-ray computed tomography faces limitations in identifying the carbon gel phase and is associated with high costs. Therefore, it is of substantial interest to directly investigate the cross-sectional pore structure from SEM morphologies. In this study, the using of resin protected polishing method to expose the cross-sectional structure is proposed to analyze the porosity evolution of the cross-sectional structure for lithium-ion battery anode. This method can clearly expose the cross-sectional structure of the electrode preventing the disturbance of the height fluctuation of the active particles. The influence of the coating processes on the pore structure is studied with the help of image J software and the machine leaning plug-in. The porosity changes of the electrode along with the coating depth are clearly elucidated. This method provides a convenient and efficient solution on the structure characterization of the electrode in Lithium-ion batteries.