Effect of slurry preparation process on electrochemical performances of LiCoO2 composite electrode

The slurries comprising LiCoO2 powder, carbon, and polymeric binder are prepared by two different mixing processes, and their rheological properties are compared. In the multi-step process, the solvent is added into solid mixture in stepwise, whereas the total amount at once in the one-step process. The former process gives the slurry that is more suitable for electrode preparation with fluid-like behavior and more uniform dispersion of solid ingredients as compared to those prepared from the letter. In the composite electrode prepared from the former, the LiCoO2 and carbon particles are homogeneously distributed without agglomeration. Indebted to this favorable feature, this electrode exhibits a better electrochemical performance for cyclability and rate capability. It is very likely that the contact resistance and charge transfer resistance for lithiation/de-lithiation are smaller in the former electrode due to the homogeneous distribution of LiCoO2 and carbon particles, which leads to a less significant electrode polarization.