A Carboranyl Electrolyte Enabling Highly Reversible Sodium Metal Anodes via a “Fluorine-Free” SEI

Anton W. Tomich, Jehee Park, Seoung Bum Son, Ethan P. Kamphaus, Xingyi Lyu, Fulya Dogan, Veronica Carta, Jihyeon Gim, Tao Li, Lei Cheng, Eungje Lee, Vincent Lavallo, Christopher S. Johnson

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

Realization of practical sodium metal batteries (SMBs) is hindered due to lack of compatible electrolyte components, dendrite propagation, and poor understanding of anodic interphasial chemistries. Chemically robust liquid electrolytes that facilitate both favorable sodium metal deposition and a stable solid-electrolyte interphase (SEI) are ideal to enable sodium metal and anode-free cells. Herein we present advanced characterization of a novel fluorine-free electrolyte utilizing the [HCB11H11]1− anion. Symmetrical Na cells operated with this electrolyte exhibit a remarkably low overpotential of 0.032 V at a current density of 2.0 mA cm−2 and a high coulombic efficiency of 99.5 % in half-cell configurations. Surface characterization of electrodes post-operation reveals the absence of dendritic sodium nucleation and a surprisingly stable fluorine-free SEI. Furthermore, weak ion-pairing is identified as key towards the successful development of fluorine-free sodium electrolytes.

Original languageEnglish
Article numbere202208158
JournalAngewandte Chemie - International Edition
Volume61
Issue number51
DOIs
StatePublished - Dec 19 2022
Externally publishedYes

Keywords

  • Anode-Free Batteries
  • Carboranes
  • Electrochemistry
  • Electrolyte Engineering
  • Sodium Metal Anodes

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