Schematic illustration

Major Contributions

1. A synergistic modification strategy combining TiNb₂O₇ surface coating and Ti⁴⁺ bulk doping was developed for single-crystal Ni-rich LiNi₀.₈₃Mn₀.₀₆Co₀.₁₁O₂ cathodes, effectively addressing both surface and bulk degradation mechanisms. This approach not only forms a protective layer on the cathode surface but also allows Ti⁴⁺ ions to diffuse into the bulk structure, enhancing structural integrity and suppressing detrimental side reactions.

2. The TiNb₂O₇-coated cathode demonstrated significantly improved electrochemical performance, including higher capacity retention (81.92% after 100 cycles at 1C) compared to the uncoated material (58.55%). The coating reduced lithium/nickel cation mixing, enhanced lithium-ion diffusion, and stabilized the cathode–electrolyte interface, as confirmed by advanced characterization techniques such as XPS, XRD, and electrochemical impedance spectroscopy.

3. Post-cycling analyses revealed that the TiNb₂O₇ coating preserved the layered crystalline structure of the cathode and minimized surface degradation, particle cracking, and unwanted interfacial reactions. This surface engineering strategy proved broadly effective for extending the cycle life and reliability of Ni-rich single-crystal cathode materials in high-energy lithium-ion batteries.

主要貢獻

1.開發出結合TiNb₂O₇表面包覆與Ti⁴⁺體相摻雜的協同修飾策略，應用於單晶Ni-rich LiNi₀.₈₃Mn₀.₀₆Co₀.₁₁O₂正極材料，有效同時解決表面及體相劣化問題。此方法不僅在正極表面形成保護層，還可促使Ti⁴⁺離子擴散進入體相結構，提升結構完整性並抑制有害副反應。

2.TiNb₂O₇包覆後的正極展現顯著提升的電化學性能，包括在1C條件下循環100次後容量保持率達81.92%，遠高於未包覆材料的58.55%。包覆層能有效降低鋰/鎳陽離子混雜、提升鋰離子擴散效率，並穩定正極-電解液界面，經XPS、XRD及電化學阻抗等多項先進表徵技術驗證。

3.循環後分析顯示，TiNb₂O₇包覆能維持正極層狀晶體結構，顯著減少表面劣化、顆粒裂解及不良界面反應。此表面工程策略對延長Ni-rich單晶正極材料於高能量鋰離子電池中的循環壽命與可靠性具廣泛效益。