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

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 LiNi_0.8Mn_0.1Co_0.1O₂ (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 2 C, 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 2 C, 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.