Highly concentrated carbonate electrolyte for Li-ion batteries with lithium metal and graphite anodes

Jian De Xie, Jagabandhu Patra, Purna Chandra Rath, Weng Jing Liu, Ching Yuan Su, Sheng Wei Lee, Chung Jen Tseng, Yasser Ashraf Gandomi, Jeng Kuei Chang

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Highly concentrated lithium bis(fluorosulfonyl)imide (LiFSI) salt dissolved in carbonate solvent is employed as a high-performance and robust organic electrolyte for Li-ion batteries. The influences of Li salt type, concentration, and solvent type (such as diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethylene carbonate (EC)) on the electrochemical properties of Li metal and graphite anodes are systematically assessed. A superior electrolyte composition of 5.5 M LiFSI-DMC/EC is achieved, enhancing the anti-flammability, coulombic efficiency, and high rate capability. The optimal efficiency values of Li electrodeposition/stripping utilizing 5.5 M LiFSI-DMC/EC are 97.0% and 94.5% at 0.4 and 6 mA cm−2, respectively. Such an enhanced performance is due to the formation of a three-dimensional ion network, composed of contact ion pairs (CIPs) and ion aggregates (AGGs) in the highly concentrated LiFSI electrolyte, which effectively decreases the number of free solvent molecules and inhibits the formation of undesired dendritic Li structures. Raman spectroscopy is employed to confirm the formation of CIP and AGG compounds within the electrolyte. The electrochemical data of the 5.5 M LiFSI-DMC/EC electrolyte cell demonstrates a remarkable improvement in the specific capacity and rate capability of a graphite anode.

Original languageEnglish
Article number227657
JournalJournal of Power Sources
Volume450
DOIs
Publication statusPublished - 2020 Feb 29

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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