Presentation Title：Niobium-Tungsten Epitaxial Entropy-Assisted Coating Suppresses Strain Propagation in Ultra-High Nickel Cathodes During Fast Charging

Abstract：

Surface reconstruction and the accompanying severe strain propagation have long been identified as the primary causes of cathode failure in ultrahigh-Ni LiNi_xCo_yMn_1−x−yO₂ (x ≥ 0.9) during fast charging and long-term cycling. Although extensive efforts have been made, existing strategies fail to simultaneously tackle electro-chemomechanical instability without compromising energy and power density. To address this challenge, this study proposes an epitaxial entropy-assisted coating strategy for ultrahigh-Ni cathodes. The coating is formed through an oriented attachment-driven reaction between Wadsley–Roth phase-based oxides and layered-oxide cathodes. This entropy-assisted surface exhibits high anti-cracking and anti-corrosion capabilities, along with fast ionic transport properties that significantly enhance the fast charging/discharging performance, wide temperature tolerance, and thermal stability of the ultrahigh-Ni cathodes. Comprehensive multi-scale in situ synchrotron X-ray analyses, covering primary/secondary particle levels to the electrode level, demonstrate that even when charged beyond the 75% state-of-charge threshold of layered cathodes, the coated cathodes show substantially reduced lattice dislocations, anisotropic lattice strain, and oxygen release, alongside improved bulk and local structural stability.

Bio:

Chen Zhao, he is an assistant professor of Fudan University，enthusiastic young researcher with 8+ years of experience in developing advanced energy storage battery systems and 5+ years of experience in conducting various synchrotron-related experiments including ex-situ/in-situ materials imaging, scattering, diffraction, and adsorption to gain an in-depth understanding of the working principles and failure mechanism for a wide category of materials such as metal, layered metal oxide, sulfur/selenium, solid-state electrolyte, etc.