Crack initiation and propagation are associated with the build-up of capillary pressure during the drying process. To avoid the cracking problem during drying, the followings are good ways,

  1. Adding another solvent to reduce surface tension of slurry
  2. Improve wettability
  3. Decrease capillary pressure during drying

Source link:

https://ecs.confex.com/ecs/232/webprogram/Paper104446.html

Abstract

Aqueous processing of Li-ion battery electrodes promises to reduce cost due to the elimination of the toxic solvent N-Methyl-2-pyrrolidone (NMP) [1]. It has been reported that good rate performance and cycling performance can be achieved by aqueous processing of lithium nickel manganese cobalt oxides (LiNi0.5Mn0.3Co0.2O2, NMC532) at ~2 mAh/cm2 loading [2]. To further increase the energy density of Li-ion cells, the loading needs to be increased to at least ~4 mAh/cm2 [3]. However, loading increases to this level using aqueous processing introduce critical cracking issues leading to poor performance [4].

This work reports the importance of surface tension control in the preparation of slurries for coating manufacturing with high areal loadings. Crack initiation and propagation associated with the build-up of capillary pressure during the drying process will be discussed. The surface tension of the slurry is reduced by the addition of another solvent, which leads to improved wettability and decreased capillary pressure during drying. The critical thickness (areal loading) without cracking increases gradually with decreasing surface tension. The electrochemical performance of pouch cells will also be discussed.