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Structures of Solid‐Electrolyte Interphases and Impacts on Initial‐Stage Lithium Deposition in Pyrrolidinium‐Based Ionic Liquids
Author(s) -
He JunWu,
Gu Yu,
Wang WeiWei,
Wang JunHao,
Chen ZhaoBin,
He HongYan,
Wu QiHui,
Yan JiaWei,
Mao BingWei
Publication year - 2021
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.202001277
Subject(s) - deposition (geology) , electrolyte , lithium (medication) , cyclic voltammetry , nucleation , diffusion , x ray photoelectron spectroscopy , materials science , chemical engineering , ionic liquid , ionic bonding , inorganic chemistry , chemistry , chemical physics , analytical chemistry (journal) , ion , electrode , electrochemistry , thermodynamics , organic chemistry , geology , medicine , paleontology , physics , endocrinology , catalysis , sediment , engineering
Electrodeposition of lithium is of both fundamental significance and practical importance. However, Li deposition has to proceed beneath a solid‐electrolyte interphase (SEI). Herein, we present a fundamental study on the formation of SEIs and their influences on Li initial‐stage deposition on Cu in Py 14 cation‐based ionic liquids (ILs) combined with different ratios of TFSI and FSI anions. Different SEIs are pre‐formed on Cu by using cyclic voltammetry, followed by detailed characterizations by XPS and AFM, which elucidate that all the SEIs bear mosaic‐like I−O structures but with different compositions and structures and varying thicknesses of approximately 60–150 nm. The Li initial‐stage depositions are studied by using cyclic voltammetric and potential stepping techniques, and current‐time transients are analyzed with the aid of the Scharifker‐Hills model. Discrepancies in nucleation density and diffusion coefficients and their relationships with overpotentials are investigated in correlation with the SEI structures. The present work demonstrates that interfacial and bulk properties of SEI strongly affect the Li deposition processes, which provides opportunities for uniform Li deposition.