Analysis of the Effect of Particle Shape on Pore Structure

Abstract

Market requirements for lithium-ion batteries are gradually increasing as they expand their applications from small electronic devices to large EVs and ESSs. Various active materials, binders, and conductive materials could be used to make batteries. In manufacturing electrodes, the microstructure of each porous electrode will vary depending on the size and shape of the particles used 1. Many studies show that the microstructure of lithium-ion battery electrodes affects cell resistance, cycle life, and rate capabilities. In this study, electrodes with various mass loading levels and composite densities were fabricated using primary and secondary particle NCM cathode active materials. Two major parameters of the porous electrode, porosity and tortuosity, were obtained. Mercury intrusion porosimetry was used to measure porosity. Tortuosity was obtained from Bruggeman’s relationship 2,3, using electrochemical impedance spectroscopy (EIS). We compared porosity and tortuosity values with the SEM image of an electrode. It was confirmed that the pore structure can be well maintained in the primary particle NCM based electrode due to the high stiffness of the active material.