Evolution of the rate-limiting step: From thin film to thick Ni-rich cathodes

Abstract Ni-rich NMC (LiNixMnyCo1-x-yO2, x ≥ 0.6) has the attributes of high specific capacity (greater than 180 mAh/g), high operating voltage (ca. 3.8 V) and low cost, which is therefore deemed as one of the most promising cathode candidates for next-generation high-energy Li-ion batteries (LIBs). However, challenges exist before the large-scale commercialization of Ni-rich cathode such as gas generation, capacity degradation especially at high rates or elevated temperatures. From thin film to densely packed high loading cathode, this work investigates the rate-limiting steps in Ni-rich cathode e.g., phase structure, electronic and ionic conductivity to understand the reaction kinetics at different scales. This work provides new insights in understanding the electrochemical properties of Ni-rich cathode at different levels to inspire revolutionary ideas to address the fundamental issues of Ni-rich cathode from material to relevant electrode levels.