Electrochemical interface modification strategies for high-performance Ni cathodes: a comprehensive review and outlook

초록

The rapid rise of electric vehicles drives the need for better battery energy density. Nickel-rich NCM (lithium-nickel-manganese-cobalt oxides) cathodes offer high-energy density but face challenges like cycle performance degradation and safety issues in lithium-ion batteries. These challenges include interfacial reactions, structural changes, and thermal decomposition, leading to CEI (cathode-electrolyte interface) layer formation, high-temperature NCM decomposition, and reactions with the electrolyte. Recent research focuses on cathode surface modifications, electrolyte additives, and solid electrolytes to address these issues. Enhancing Ni-rich NCM cathode performance involves doping and coating. Doping stabilizes the crystal structure and reduces oxygen release, alleviating voltage and capacity degradation. Coating reduces harmful side reactions and is crucial for optimizing performance and stability. Electrolyte additives improve battery performance and stability. This paper summarizes research on understanding and mitigating surface degradation, mechanical failure, and thermal instability in nickel-rich NCM cathodes. Proposed solutions include surface modification, electrolyte selection, and additive use to enhance interfacial stability and battery safety at high voltages.

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