Direct mapping of charge distribution during lithiation of Ge nanowires using off-axis electron holography

Zhaofeng Gan, Meng Gu, Jianshi Tang, Chiu Yen Wang, Yang He, Kang L. Wang, Chongmin Wang, David Smith, Martha McCartney

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

The successful operation of rechargeable batteries relies on reliable insertion/extraction of ions into/from the electrodes. The battery performance and the response of the electrodes to such ion insertion and extraction are directly related to the spatial distribution of the charge and its dynamic evolution. However, it remains unclear how charge is distributed in the electrodes during normal battery operation. In this work, we have used off-axis electron holography to measure charge distribution during lithium ion insertion into a Ge nanowire (NW) under dynamic operating conditions. We discovered that the surface region of the Ge core is negatively charged during the core-shell lithiation of the Ge NW, which is counterbalanced by positive charge on the inner surface of the lithiated LixGe shell. The remainder of the lithiated LixGe shell is free from net charge, consistent with its metallic characteristics. The present work provides a vivid picture of charge distribution and dynamic evolution during Ge NW lithiation and should form the basis for tackling the response of these and related materials under real electrochemical conditions.

Original languageEnglish (US)
Pages (from-to)3748-3753
Number of pages6
JournalNano Letters
Volume16
Issue number6
DOIs
StatePublished - Jun 8 2016

Keywords

  • charge distribution
  • electron holography
  • in situ TEM
  • Lithium ion battery

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanical Engineering

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