Enhancing structural and thermal stability of ultrahigh-Ni cathodes via anion-cation codoping induced surface reconstruction strategy

The rapid expansion of the automotive sector has significantly increased the demand for high-performance lithium-ion batteries, positioning Ni-rich layered cathodes as a promising solution due to their high energy density and cost-efficiency. However, these cathodes face critical challenges, including thermal instability and structural degradation at an elevated temperature, which hinder their practical application. This study introduces an advanced surface reconstruction strategy combining a LiScF₄ coating, Sc/F surface co-doping, and a cation-mixing layer to address these issues. The LiScF₄ coating serves as a durable protective barrier, reducing electrolyte decomposition, minimizing transition metal dissolution, and enhancing lithium-ion transport. Sc/F surface co-doping stabilizes lattice oxygen by increasing the energy barrier for oxygen vacancy formation and minimizing oxygen release, thereby suppressing phase transitions and interfacial side reactions. Additionally, the cation-mixing layer improves interfacial stability by alleviating lattice strain and supporting reversible cation migration, ensuring prolonged durability during cycling and under high-temperature conditions. These integrated modifications work synergistically to mitigate various degradation mechanisms, significantly improving the thermal stability, structural integrity, and electrochemical performance of Ni-rich cathodes. This approach offers a viable pathway for incorporating Ni-rich cathodes into advanced lithium-ion batteries, making them well-suited for applications requiring high thermal stability. Moreover, this research provides valuable guidance for the development of a multi-component modification strategy, paving the way for future innovations in energy storage materials and advancing high-performance battery technology.