Elucidating the mechanical-electrochemical interactions in single crystalline LiNi07Co01Mn02O2 cathode material during solid-state calcination

In recent years, the shift towards single-crystalline Ni-rich LiNixCoyMn1-x-yO2 (NCM) cathode materials has intensified the focus on temperature regulation via the solid-state method, aiming to enhance electrochemical capacity and control crystal size. This study investigates how variations in crystal size, indicative of distinct lattice structures, affect lithium ion transport during the electrochemical charging/discharging cycle. Our findings reveal mechanical degradation in NCM samples correlating with increased sintering temperatures of LiOH.H2O and NCMOH precursors, as evidenced by nanoindentation tests measuring elastic modulus and hardness. Elevated sintering temperatures were observed to facilitate nucleation and crystal growth, albeit introducing oxygen vacancies potentially detrimental to the initial Coulombic Efficiency within the NCM lattice. This degradation in both mechanical and electrochemical properties underscores the critical impact of sintering temperature on structural integrity. Our systematic analysis provides essential insights into the interplay between structural characteristics and electrochemical performance, offering compelling evidence for the optimization of sintering temperatures in the preparation of NCM cathode materials.