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Title: Lithium electrodeposition dynamics in aprotic electrolyte observed in situ via transmission electron microscopy

Electrodeposited metallic lithium is an ideal negative battery electrode, but nonuniform microstructure evolution during cycling leads to degradation and safety issues. A better understanding of the Li plating and stripping processes is needed to enable practical Li-metal batteries. Here we use a custom microfabricated, sealed liquid cell for in situ scanning transmission electron microscopy (STEM) to image the first few cycles of lithium electrodeposition/dissolution in liquid aprotic electrolyte at submicron resolution. Cycling at current densities from 1 to 25 mA/cm2 leads to variations in grain structure, with higher current densities giving a more needle-like, higher surface area deposit. The effect of the electron beam was explored, and it was found that, even with minimal beam exposure, beam-induced surface film formation could alter the Li microstructure. The electrochemical dissolution was seen to initiate from isolated points on grains rather than uniformly across the Li surface, due to the stabilizing solid electrolyte interphase surface film. As a result, we discuss the implications for operando STEM liquid-cell imaging and Li-battery applications.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
1235316
Report Number(s):
SAND--2015-2431J
Journal ID: ISSN 1936-0851; 579677
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
ACS Nano
Additional Journal Information:
Journal Volume: 9; Journal Issue: 4; Journal ID: ISSN 1936-0851
Publisher:
American Chemical Society
Research Org:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
lithium electrodeposition; liquid-cell electron microscopy; electron beam radiolysis; lithium-ion battery; solid electrolyte interphase; in situ TEM