Strategies to enhance Li+ transference number in liquid electrolytes for better lithium batteries

Pan ZHOU, Xiaokun ZHANG*, Yong XIANG*, Kai LIU*

*Corresponding author for this work

Research output: Journal PublicationsReview articleOther Review

31 Citations (Scopus)

Abstract

Growing market demand from portable electronics to electric automobiles boosts the development of lithium-ion batteries (LIBs) with high energy density and rate performance. However, strong solvation effect between lithium ions (Li+) and solvent molecules in common electrolytes limits the mobility of Li+ ions in electrolytes. Consequently, anions dominate the charge conduction in electrolytes, and in most cases, the value of Li+ transference number (T+) is between 0.2 and 0.4. A low T+ will aggravate concentration polarization in the process of charging and discharging, especially at high rate, which not only increases the overpotential but also intensifies side reactions, along with uneven deposition of lithium (Li) and the growth of lithium dendrites when lithium metal is used as anode. In this review, promising strategies to improve T+ in liquid electrolytes would be summarized. The migration of Li+ ions is affected directly by the types and concentration of lithium salts, solvents, and additives in bulk electrolytes. Besides, Li+ ions will pass through the separator and solid electrolyte interphase (SEI) when transferring between anodes and cathodes. With this in mind, we will classify and summarize threads of enhancing T+ from five aspects: lithium salts, solvents, additives, separators, and SEI based on different mechanisms, including covalently bonding, desolvation effect, Lewis acid-base interaction, electrostatic interaction, pore sieving, and supramolecular interaction. We believe this review will present a systematic understanding and summary on T+ and point out some feasible threads to enhance battery performance by enhancing T+. [Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)8055-8071
Number of pages17
JournalNano Research
Volume16
Issue number6
Early online date27 Sept 2022
DOIs
Publication statusPublished - Jun 2023
Externally publishedYes

Bibliographical note

We gratefully acknowledge support by the National Natural Science Foundation of China (Nos. 22071133 and 21905040), the Tsinghua University-China Petrochemical Corporation Joint Institute for Green Chemical Engineering (No. 421120), Tsinghua-Foshan Innovation Special Fund (TFISF, No. 2020THFS0130), and Tsinghua University Initiative Scientific Research Program.

Keywords

  • Li transference number
  • lithium batteries
  • mechanisms
  • rate performance
  • strategies

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