Predicting the Stoichiometric Ratio of Synthesized Hydroxides in Nickel‐Rich Cathode Precursors of Lithium‐Ion Batteries by Using a Computational Thermodynamics Model

Abstract

Layered oxide cathode materials are synthesized by performing multiple experiments. Optimizing the structure and morphology of cathode particles requires repeated experiments with different operating parameters, such as pH, ammonia concentration, reaction temperature, and stirring speed. Because numerous tests are necessary to achieve the optimal cathodic structure, significant cost and time are required, which can be reduced by modeling the precipitation process. Herein, nucleation steps in the reactor are focused on to understand various physical phenomena that occur during the coprecipitation synthesis process. The computational model can predict the stoichiometric ratio of transition‐metal‐hydroxide precursors synthesized during the coprecipitation process at different pH values and different ammonia concentrations inside the reactor and identify synthesis conditions needed for obtaining a specific stoichiometric ratio of transition‐metal‐hydroxide precursors. To confirm modeling results, several coprecipitation synthesis processes are performed. Experimental results are compared with modeling results. By using the model, 2 m ammonia concentration and pH 11.5 are determined to be optimal for the synthesis of LiNi x Co y Mn z O2 (NCM)811 hydroxide precursors. Experiments performed to confirm modeling results indicate that the hydroxide material synthesized in the mentioned conditions has higher tap density and better electrochemical performance in the battery test.