文献类型：期刊文献

英文题名：Surface Gradient Engineering Relaxes Stress Concentration in Ultrahigh-Ni Cathodes, Enabling Superior Cyclability in Pouch Cells

作者：Yu, Haifeng[1];Guo, Wenshuai[2];Yao, Liyun[2];Zhang, Li[3];Chen, Ling[2];Jiang, Hao[1,2,3];Li, Chunzhong[1,2]

机构：[1]East China Univ Sci & Technol, Shanghai Engn Res Ctr Hierarch Nanomat, Sch Chem Engn, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Sch Mat Sci & Engn, Key Lab Ultrafine Mat, Minist Educ, Shanghai 200237, Peoples R China;[3]Xinjiang Univ, Sch Chem Engn, State Key Lab Chem & Utilizat Carbon Based Energy, Urumgi 830046, Xinjiang, Peoples R China

年份：2025

卷号：25

期号：43

起止页码：15723

外文期刊名：NANO LETTERS

收录：;EI(收录号：20254419420717);WOS:【SCI-EXPANDED(收录号:WOS:001593145400001)】；

基金：This work was supported by the National Natural Science Foundation of China (U22A20429), the Shanghai Pilot Program for Basic Research (22TQ1400100-13), the Major Science and Technology Projects of Xinjiang Uygur Autonomous Region (2024A01001), and the Fundamental Research Funds for the Central Universities.

语种：英文

外文关键词：Li-ion batteries; Ni-rich cathodes; gradientengineering; cycle life

摘要：Developing ultrahigh-Ni cathodes is critical for advancing next-generation high-energy Li-ion batteries (LIBs), yet reducing the Co content exacerbates mechanochemical degradation and lowers Li-ion transport. Herein, we design a surface low-Co-gradient-distributed and bulk Mg-doped Li(Ni0.97Mn0.03)0.995Ge0.005O2 (GM-g-NMC) cathode, in which nonmagnetic Ge substitution for Co not only stabilizes the crystal structure synergistically with Mg but also promotes a near-surface Co gradient distribution by suppressing its diffusion. These features mitigate lattice contraction while enhancing surface mechanical robustness, thereby relaxing the stress concentration and preserving structural and interfacial stability. Operando characterizations and electrochemical analyses reveal a 5-fold reduction in potential polarization, along with the suppression of rock-salt phase formation. Consequently, GM-g-NMC delivers an ultrahigh reversible capacity of 229.0 mAh g-1 at 0.1C and 151.7 mAh g-1 at 10C. In pouch-type full cells, it retains 80.1% of its initial capacity after 1200 cycles at 1C, prolonging the service period relative to the previously reported ultrahigh-Ni cathodes.