Intensive Dry and Wet Mixing Influencing the Structural and Electrochemical Properties of Secondary Lithium-Ion Battery Cathodes

Abstract

Different dry and wet mixing devices are investigated in this study in order to outline the importance of these often neglected process steps. Influences on structural and electrochemical properties of the manufactured electrodes, here LiNi_1/3Co_1/3Mn_1/3O₂ cathodes, are presented. Both, dry and wet mixing, are identified to influence the properties of all intermediate products as well as the electrodes’ structure and, essentially, electrochemical behavior during power test. Besides the interesting results for powder mixtures and resulting suspensions viscosities, three of the process variations lead to cathodes with a distinctive binder - carbon black network between the NMC particles. In contrast, high intensive dry mixing is revealed to inhibit the network formation. Mercury intrusion measurements quantify to which extent the lack of this network changes the pore size distribution in the electrode matrix. Power tests of full cells are used to identify the relation between the electrode’s electrochemical performance and the structural changes.