High-valence Ni 3+ construction and stability by electrochemical de-lithiation boosting oxygen evolution

• Published in: Materials chemistry frontiers 2023-11, Vol.7 (22), p.5868-5878
• Main Authors: Li, Shujing, Zhu, Xiaoming, Wang, Xiaohan, Luo, Wenshu, Yu, Xu, Guo, Qiuyun, Song, Kunming, Tian, Han, Cui, Xiangzhi, Shi, Jianlin
• Format: Article
• Language: English
• ISSN: 2052-1537; 2052-1537
• DOI: 10.1039/D3QM00633F

The development of inexpensive and efficient oxygen evolution reaction (OER) catalysts is crucial for the large-scale application of water splitting to produce green hydrogen. Different from traditional preparation methods, in this study, the electronic structure of ternary NCM (LiNi 0.94 Co 0.05 Mn 0.01 O 2 ) was directly reconstructed from the cathode of spent lithium-ion batteries through electrochemical de-lithiation technology to obtain efficient OER catalysts. The optimized NCM94-1V-90 min exhibits a low overpotential of 270 mV at 10 mA cm −2 along with excellent stability for a 300 h durability test. The high OER performance is attributed to the electronic structure reconstruction and microstructure transformation during electrochemical de-lithiation, which generates a large number of high-valence Ni 3+ and O vacancies as well as structural fragmentation, respectively, supplying more active sites and enhancing electronic conductivity, also confirmed by the density functional theory (DFT) theoretical calculation. The strategy of electrochemical de-lithiation technology to improve the OER electrocatalytic performance not only can recycle the cathode materials of lithium-ion batteries, but can also be extended to other electrode materials of spent batteries.