Investigating the Structure and Performance of Electrodes Made by Dry and Wet Slurry Processes

Abstract

Performance, cost, and safety are vital factors in producing and handling lithium-ion batteries. Using a dry process reduces the cost and environmental impact of producing large-scale lithium-ion battery electrodes significantly as solvents are eliminated. Thus, in this study, solvent-free dry electrostatic spray deposition (ESD) and conventional slurry processes were compared to uncover the influence of the manufacturing process on thick LiNi0.8Mn0.1Co0.1O2 (NMC 811) positive electrodes. More pressure during calendering was found necessary for the dry-made (dry) electrodes to have the same porosity, leading to more cracks within the NMC particles and better adhesion. At slower discharge rates, below 2C, the dry electrodes exhibited a higher specific capacity or about the same capability than that of the slurry-made ones. At higher discharge rates, greater than 2C, both types of electrodes have poor rate performance, though the slurry-made (slurry) electrodes had a slightly higher capacity. Despite more calendering-induced cracks in the dry electrodes, both electrodes had comparable long-term cycling behavior when tested in full cells with graphite-negative electrodes. This study shows the viability of using the dry-powder ESD process for manufacturing thick electrodes with high active material content, meeting the need for high energy demand.