Citraconic anhydride as an electrolyte additive to improve the high temperature performance of LiNi0.6Co0.2Mn0.2O2/graphite pouch batteries

An unstable solid electrolyte interface (SEI) on graphite electrode surface is easily destroyed and continually consumes the electrolyte for reconstruction, resulting in large capacity loss under high temperature operation. Here, citraconic anhydride (CAn) as a novel electrolyte additive is evaluated to overcome the aforementioned high temperature problems of the LiNi0.6Co0.2Mn0.2O2/graphite pouch cell. The cell containing 2 wt% CAn displays a superior capacity recovery capability and negligible capacity loss after storage at 60 degrees C for 15 days. Electrochemical measurements and spectroscopic techniques confirm that a high stability SEI film is formed on the graphite surface by the CAn reduction. Moreover, the CAn-derived SEI film can significantly reduce the irreversible consumption of LiPF6 and then effectively improve the high temperature performances of pouch LIBs. Differently from other additives, a certain amount of CAn component can reduce the impedance of pouch cells during high temperature storage process. These findings offer a promising high temperature additive for high-energy density commercial pouch LIBs. (C) 2019 Elsevier B.V. All rights reserved.