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Title: The Formation Mechanism of Fluorescent Metal Complexes at the Li xNi 0.5Mn 1.5O 4-δ/Carbonate Ester Electrolyte Interface

Electrochemical oxidation of carbonate esters at the Li xNi 0.5Mn 1.5O 4-δ/electrolyte interface results in Ni/Mn dissolution and surface film formation, which negatively affect the electrochemical performance of Li-ion batteries. Ex situ X-ray absorption (XRF/XANES), Raman, and fluorescence spectroscopy, along with imaging of Li xNi 0.5Mn 1.5O 4-δ positive and graphite negative electrodes from tested Li-ion batteries, reveal the formation of a variety of Mn II/III and Ni II complexes with β-diketonate ligands. These metal complexes, which are generated upon anodic oxidation of ethyl and diethyl carbonates at Li xNi 0.5Mn 1.5O 4-δ, form a surface film that partially dissolves in the electrolyte. The dissolved Mn III complexes are reduced to their Mn II analogues, which are incorporated into the solid electrolyte interphase surface layer at the graphite negative electrode. This work elucidates possible reaction pathways and evaluates their implications for Li + transport kinetics in Li-ion batteries.
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [3] ;  [1] ;  [1]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of Illinois, Chicago, IL (United States)
  3. Univ. of Illinois, Chicago, IL (United States)
Publication Date:
OSTI Identifier:
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the American Chemical Society; Journal Volume: 137; Journal Issue: 10; Related Information: NECCES partners with Stony Brook University (lead); Argonne National Laboratory; Binghamton University; Brookhaven National University; University of California, San Diego; University of Cambridge, UK; Lawrence Berkeley National Laboratory; Massachusetts Institute of Technology; University of Michigan; Rutgers University
Research Org:
Energy Frontier Research Centers (EFRC); Northeastern Center for Chemical Energy Storage (NECCES)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
energy storage (including batteries and capacitors), defects, charge transport, materials and chemistry by design, synthesis (novel materials)