Reconstruction of solvation structure at the cathode-electrolyte interface via partial de-solvation in a metal-organic framework

• Published in: Nano energy Vol. 125; p. 109566
• Main Authors: Chang, Miao, Cheng, Fangyuan, Zhang, Wen, Liao, Mengyi, Li, Qing, Fang, Chun, Han, Jiantao, Huang, Yunhui
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.06.2024
• Subjects: Cathode-electrolyte interphase; Li+ solvation structure; Lithium-ion batteries; Metal-organic frameworks; Nickel-rich layered cathode; Lithium-ion batteries; Nickel-rich layered cathode; Metal-organic frameworks; Cathode-electrolyte interphase; Li+ solvation structure
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2024.109566

The formation of cathode-electrolyte interphase (CEI) is closely related to the solvation structure in direct contact with the cathode. The de-solvated solvent molecules are subject to the attack of highly catalytic transition metal ions in the cathode materials (such as Ni-rich LiNi0.8Co0.1Mn0.1O2, Ni-rich NCM), especially at high voltage or high temperature, leading to the poor CEI structure that accelerates the deterioration of rechargeable batteries. Considerable strategies have been proposed to solve this issue. Herein, we have constructed a porous Mg-MOF buffer layer on the surface of Ni-rich NCM, which not only greatly reduces the contact between solvent molecules and cathodes to alleviate the extensive interface reactions, but also promote the de-solvation of Li+ solvation structure through strong affinity between solvents and Mg2+. The partially de-solvated structure induces the anion to participate in the solvation structure and contributes to the formation of a uniform LiF-rich CEI with superior mechanical integrity and chemical stability. Therefore, the NCM with Mg-MOF buffer layer exhibits improved cycling stability at both elevated temperature of 45 °C and high voltage of 4.5 V with lithium as anode. Moreover, the modified NCM/graphite full cells also deliver ultra-stable rechargeable capability with a remarkable capacity retention of 87.3% over 1000 cycles as compared to the only 21.7% of pristine NCM based cells. [Display omitted] •A Mg-MOF layer was constructed to reconstruct the Li+ solvation structure and enable a desired LiF-rich CEI.•Significantly alleviating the structural degradation of both the bulk and the surface.•Remarkable cycling performance were achieved under both normal and extreme working conditions.•Breaking a new path for further research on building desired interfaces in all types of layered cathodes.