Inhibiting manganese (II) from catalyzing electrolyte decomposition in lithium-ion batteries

XH Luo and LD Xing and J Vatamanu and JW Chen and JK Chen and MZ Liu and C Wang and K Xu and WS Li, JOURNAL OF ENERGY CHEMISTRY, 65, 1-8 (2022).

DOI: 10.1016/j.jechem.2021.05.022

A once overlooked source of electrolyte degradation incurred by dissolved manganese (II) species in lithium-ion batteries has been identified recently. In order to deactivate the catalytic activity of such manganese (II) ion, 1-aza-12-crown-4-ether (A12C4) with cavity size well matched manganese (II) ion is used in this work as electrolyte additive. Theoretical and experimental results show that stable com-plex forms between A12C4 and manganese (II) ions in the electrolyte, which does not affect the solvation of Li ions. The strong binding effect of A12C4 additive reduces the charge density of manganese (II) ion and inhibits its destruction of the PF6 structure in the electrolyte, leading to greatly improved thermal stability of manganese (II) ions- containing electrolyte. In addition to bulk electrolyte, A12C4 additive also shows capability in preventing Mn2+ from degrading SEI on graphite surface. Such bulk and interphasial stability introduced by A12C4 leads to significantly improved cycling performance of LIBs. (c) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

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