Solvent Reorganization and Additives Synergistically Enable High-Performance Na-Ion Batteries

Mengying Ma, Binbin Chen, Xu Yang, Yingchun Liu, Sheng Dai, Xingguo Qi, Yong Sheng Hu, Huilin Pan

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Electrolytes with high and localized salt concentrations have been successfully developed to mitigate parasitic reactions in rechargeable batteries, but at the expense of high cost, high viscosity, and slow kinetics. An alternative electrolyte design concept beyond the current strategies is crucial to reaching practical applications. From salt to solvent, herein, we demonstrate solvent reorganization to develop highly stable dilute phosphate electrolytes (0.16-0.85 M) for Na-ion batteries. This solvent reorganization is the result of optimal intermolecular interactions between the main solvent phosphate and charge-asymmetric trifluorotoluene (PhCF3) as a solvent coordinator. Appropriate solvent reorganization induced by PhCF3 can reinforce the solvation network of electrolytes without employing high concentrations of expensive salts, which enables a highly stable dilute phosphate electrolyte in combination with synergic additives. With the designed dilute electrolyte, NaCu1/9Ni2/9Fe1/3Mn1/3O2 (CNFM)||HC Na-ion full cells demonstrate stable cycling for 400 cycles and a high Coulombic efficiency of >99.95% at 0.2 C. An Ah-level pouch cell is evidenced with highly safe cycling of over 100 cycles with 90.1% capacity retention and without inflation at 60 °C. This work opens an alternative avenue in designing electrolytes by manipulating solvent interactions instead of focusing on local solvation structure and high salt concentrations.

Original languageEnglish
Pages (from-to)477-485
Number of pages9
JournalACS Energy Letters
Volume8
Issue number1
DOIs
StatePublished - Jan 13 2023
Externally publishedYes

Funding

This work was supported by the National Natural Science Foundation of China (Grant Nos. U21A2075, 22179117, 51725206), the Startup Foundation for Hundred-Talent Program of Zhejiang University, and the program of the State Key Laboratory of Clean Energy Utilization at Zhejiang (ZJUCEU2020005).

FundersFunder number
National Natural Science Foundation of China22179117, 51725206, U21A2075
National Natural Science Foundation of China
State Key Laboratory of Clean Energy UtilizationZJUCEU2020005
State Key Laboratory of Clean Energy Utilization
Startup Foundation for Hundred-Talent Program of Zhejiang University

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