Understanding the Synthesis Behavior of High-performance Ni-Based Layered Oxide Cathode Material : Comprehensive Multi-Scale Investigation

Abstract

With various reasons such as high energy density and tunable composition, Ni-based layered oxide cathodes are currently under active investigation. However, the synthesis behavior and conditions vary based on the composition and ratio of the transition metal. We propose a method for understanding the synthesis behavior of materials with different compositions using High Ni NCM and Mid-Ni Co-free NM, which is nearly devoid of the expensive and toxic Co. In the case of High-Ni NCM, the substantial Ni content facilitates the relatively facile formation of a layered structure. Nevertheless, cracks formed during charge-discharge significantly contribute to degradation. Hence, we employed a method to observe and adjust the synthesis behavior at the micro scale. On the other hand, Mid-Ni Co-free NM, with Co absence and high Mn content, faces challenges in reaching a complete layered structure. Consequently, we enhanced performance by understanding and improving the arrangement of atoms. Our study provides insights into understanding and strategizing synthesis behavior at multiple scales.