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Title: In Situ STEM-EELS observation of nanoscale interfacial phenomena in all-solid-state batteries

Behaviors of functional interfaces are crucial factors in the performance and safety of energy storage and conversion devices. Indeed, solid electrode–solid electrolyte interfacial impedance is now considered the main limiting factor in all-solid-state batteries rather than low ionic conductivity of the solid electrolyte. Here, we present a new approach to conducting in situ scanning transmission electron microscopy (STEM) coupled with electron energy loss spectroscopy (EELS) in order to uncover the unique interfacial phenomena related to lithium ion transport and its corresponding charge transfer. Our approach allowed quantitative spectroscopic characterization of a galvanostatically biased electrochemical system under in situ conditions. Using a LiCoO2/LiPON/Si thin film battery, an unexpected structurally disordered interfacial layer between LiCoO2 cathode and LiPON electrolyte was discovered to be inherent to this interface without cycling. During in situ charging, spectroscopic characterization revealed that this interfacial layer evolved to form highly oxidized Co ions species along with lithium oxide and lithium peroxide species. Here, these findings suggest that the mechanism of interfacial impedance at the LiCoO2/LiPON interface is caused by chemical changes rather than space charge effects. Insights gained from this technique will shed light on important challenges of interfaces in all-solid-state energy storage and conversion systems and facilitatemore » improved engineering of devices operated far from equilibrium.« less
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [2] ;  [2] ;  [4] ;  [4] ;  [1]
  1. Univ. of California, San Diego, La Jolla, CA (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Univ. of California, San Diego, La Jolla, CA (United States); Amrita Vishwa Vidyapeetham Univ., Kerala (India)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
OSTI Identifier:
1257962
Report Number(s):
BNL--112300-2016-JA
Journal ID: ISSN 1530-6984; KC0403020
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 16; Journal Issue: 6; Journal ID: ISSN 1530-6984
Publisher:
American Chemical Society
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE solid state battery; Center for Functional Nanomaterials; lithium ion battery; thin film battery; in situ TEM; interfacial phenomena; solid electrolyte