High-Li+-fraction ether-side-chain pyrrolidinium–asymmetric imide ionic liquid electrolyte for high-energy-density Si//Ni-rich layered oxide Li-ion batteries

Bharath Umesh, Purna Chandra Rath, Jagabandhu Patra, Rahmandhika Firdauzha Hary Hernandha, Subhasis Basu Majumder, Xinpei Gao, Dominic Bresser, Stefano Passerini, Hong Zheng Lai, Tseng Lung Chang, Jeng Kuei Chang

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15 Citations (Scopus)

Abstract

In this study, Si nanoparticles with interweaving carbon nanotubes are wrapped by graphitic sheets to achieve high conductivity and high dimensional stability of a composite anode (denoted as Si/CNT/G) for Li-ion batteries. In addition, an ionic liquid (IL) electrolyte that consists of ether-side-chain pyrrolidinium, asymmetric imide, and a high Li+ fraction is prepared. This electrolyte is for the first time employed for Si-based Li-ion batteries. Decomposition of the ether groups creates organic components in the solid electrolyte interphase (SEI). The high Li+ concentration promotes decomposition of the (fluorosulfonyl)(trifluoromethanesulfonyl)imide (FTFSI) anions, leading to a LiF- and Li3N-rich SEI. The organic-inorganic balanced SEI is responsible for the excellent charge-discharge properties of the Si/CNT/G anode. The FTFSI anions exhibit low corrosivity toward the Al current collector and high compatibility with the LiNi0.8Co0.1Mn0.1O2 (NCM-811) cathode. With a charging voltage of 4.5 V, remarkable reversible capacities and cycling stability of NCM-811 in the high-Li+-fraction N-methoxyethyl-N-methylpyrrolidinium/FTFSI IL electrolyte are observed. Differential scanning calorimetry is used to examine the interfacial exothermic reactions between the delithiated NCM-811 and various electrolytes. After 300 charge-discharge cycles, the capacity retention of a Si/CNT/G||NCM-811 full cell with the proposed IL electrolyte is 80% with a Coulombic efficiency of ∼99.9%. These values are significantly higher than those of the conventional carbonate electrolyte cell.

Original languageEnglish
Article number132693
JournalChemical Engineering Journal
Volume430
DOIs
Publication statusPublished - 2022 Feb 15

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering

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