Slow stabilization of Si-Li alloys formed during charge and discharge processes in a Si-carbon mixed electrode studied by insitu solid-state 7Li nuclear magnetic resonance spectroscopy

J. Arai, Kazuma Gotoh, R. Sayama, K. Takeda

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The charge-discharge behavior of a Si-C (Si:graphite = 20:80 wt%) mixed electrode was investigated by in-situ solid-state 7Li nuclear magnetic resonance (NMR) spectroscopy. The spectra revealed the formation of Li-Si alloys and the intercalation of Li into graphite during the charge process and the corresponding reverse process (Li extraction) during discharge. Li was mainly stored as a Li-Si alloy (Li15Si4) at high SOC (State of Charge) values (above 80% SOC, low cell voltage region) and could be released from the same compound. The cell resistance measured by electrochemical impedance spectroscopy (EIS) increased steeply at high SOC values, revealing structural changes in the Li-Si alloy. The result is consistent with the gradual decrease of the Li15Si4 signal intensity in the NMR spectra observed immediately after a discharge process at 80% SOC.

Original languageEnglish
Title of host publication18th International Meeting on Lithium Batteries
PublisherElectrochemical Society Inc.
Pages141-151
Number of pages11
Volume73
Edition1
ISBN (Electronic)9781607685395
DOIs
Publication statusPublished - 2016
Event18th International Meeting on Lithium Batteries, IMLB 2016 - Chicago, United States
Duration: Jun 19 2016Jun 24 2016

Other

Other18th International Meeting on Lithium Batteries, IMLB 2016
CountryUnited States
CityChicago
Period6/19/166/24/16

ASJC Scopus subject areas

  • Engineering(all)

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