Pinning the Surface Layered Oxide Structure in High Temperature Calcination Using Conformal Atomic Layer Deposition Coating for Fast Charging Cathode

Abstract

In the solid-state synthesis of layered oxides, achieving cathode powder with precise morphology, crystal structure, and surface properties demands a delicate balance between thermodynamics and kinetics. Elevated temperatures are indispensable for driving the reaction toward completion, facilitating the formation of ordered layered structures essential for efficient lithium-ion transportation in Li-ion batteries. However, high temperatures risk inducing Li/Ni mixing and rock-salt formation, particularly pronounced in layered oxides rich in Ni content, detrimentally impacting their performance. To address this challenge, the approach involves a precisely designed conformal coating with a high affinity for oxygen atoms, strategically employed to pin the surface layered oxide structure even under elevated temperatures. By preventing undesired surface decomposition during the high-temperature lithiation process, this innovation fosters the formation of well-ordered layered structures on the surface. Consequently, this pioneering strategy substantially mitigated phase separation during high-rate cycling, thereby unlocking exceptional rate capability and cycle stability in layered oxide cathodes. The strategy establishes a new pathway for synthesizing next-generation, high-power density battery materials.