A novel study on COF-based semi-solid electrolyte for spinel LiNi0.5Mn1.5O4 targeting transition metals migration

• Published in: Scripta materialia Vol. 223; p. 115101
• Main Authors: Zhao, Hong, Ren, Yaqi, Bo, Xiangkun, Si, Liping, Wei, Zhaohuan, Daoud, Walid A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15-01-2023
• Subjects: Cobalt-free cathode; Covalent organic framework; LiNi0.5Mn1.5O4; Semi-solid electrolyte; Covalent organic framework; LiNi0.5Mn1.5O4; Cobalt-free cathode; Semi-solid electrolyte
• ISSN: 1359-6462; 1872-8456
• DOI: 10.1016/j.scriptamat.2022.115101

Cobalt-free battery is one of the development trends of lithium-ion batteries. High-voltage LiNi0.5Mn1.5O4 (LNMO) with high theoretical energy density is one of the most promising Co-free cathode materials in the further. However, the side reaction between the LNMO electrode and electrolyte at high voltage or high temperature and the corresponding by-products (e.g. Mn2+/Mn3+ and Ni2+) severely deteriorate the battery performance. In this work, an anionic covalent organic framework (COF)–based semi-solid electrolyte was constructed by synthesizing a free-standing COF film with a small amount of liquid electrolyte. Further, the experimental results proved that the cycling and C-rate performance of LNMO battery is improved by using the semi-solid electrolyte. This can be proposed that the anionic COF is capable of absorbing strongly the Mn3+/Mn2+ and Ni2+ through Coulomb interaction, restraining their destructive migration to the anode. Therefore, this work will be beneficial to the commercialization of LNMO cathode material.
In this work, an anionic COF–based semi-solid electrolyte was constructed. The COF–based semi-solid electrolyte can suppress the transition metals (by-products) from migrating to the anode through Coulomb interaction, finally benefitting the full cell performance. [Display omitted]