Surface enrichment and diffusion enabling gradient-doping and coating of Ni-rich cathode toward Li-ion batteries

• Published in: Nature communications Vol. 12; no. 1; p. 4564
• Main Authors: Yu, Haifeng, Cao, Yueqiang, Chen, Long, Hu, Yanjie, Duan, Xuezhi, Dai, Sheng, Li, Chunzhong, Jiang, Hao
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 27-07-2021; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 140/146; 147/135; 147/137; 147/143; 639/301/299/891; 639/4077/4079/891; Aluminum; Batteries; Cathodes; Coatings; Commercialization; Crystal structure; Diffusion coating; Disintegration; Fading; Finite element method; Humanities and Social Sciences; Interface stability; Interstices; Lithium; Lithium-ion batteries; Mathematical models; multidisciplinary; Oxalic acid; Rechargeable batteries; Science; Science (multidisciplinary); Side reactions; Structural stability; Surface stability; Thermal runaway; X-ray diffraction
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-24893-0

Critical barriers to layered Ni-rich cathode commercialisation include their rapid capacity fading and thermal runaway from crystal disintegration and their interfacial instability. Structure combines surface modification is the ultimate choice to overcome these. Here, a synchronous gradient Al-doped and LiAlO
2
-coated LiNi
0.9
Co
0.1
O
2
cathode is designed and prepared by using an oxalate-assisted deposition and subsequent thermally driven diffusion method. Theoretical calculations, in situ X-ray diffraction results and finite-element simulation verify that Al
3+
moves to the tetrahedral interstices prior to Ni
2+
that eliminates the Li/Ni disorder and internal structure stress. The Li
+
-conductive LiAlO
2
skin prevents electrolyte penetration of the boundaries and reduces side reactions. These help the Ni-rich cathode maintain a 97.4% cycle performance after 100 cycles, and a rapid charging ability of 127.7 mAh g
−1
at 20 C. A 3.5-Ah pouch cell with the cathode and graphite anode showed more than a 500-long cycle life with only a 5.6% capacity loss.
The commercialisation of promising Ni-rich cathodes is limited by capacity fading and thermal runaway. Here, the authors design a gradient Al-doped and LiAlO
2
-coated LiNi
0.9
Co
0.1
O
2
cathode, which addresses the crystal degradation and interfacial instability and thus improves the cycle and thermal stabilities.