title: The formation mechanism of fluorescent metal complexes at the Li(x)Ni(0.5)Mn(1.5)O(4-δ)/carbonate ester electrolyte interface.
abstract: Electrochemical oxidation of carbonate esters at the Li(x)Ni(0.5)Mn(1.5)O(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(x)Ni(0.5)Mn(1.5)O(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(x)Ni(0.5)Mn(1.5)O(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.
authors.affiliation: †Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
authors.forename: Angélique
authors.initials: A
authors.lastname: Jarry
authors.affiliation: †Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Gottis
authors.affiliation: ‡Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.|§Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607, United States.
authors.forename: Young-Sang
authors.initials: YS
authors.lastname: Yu
authors.affiliation: ‡Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
authors.forename: Josep
authors.initials: J
authors.lastname: Roque-Rosell
authors.affiliation: §Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607, United States.
authors.forename: Chunjoong
authors.initials: C
authors.lastname: Kim
authors.affiliation: §Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607, United States.
authors.forename: Jordi
authors.initials: J
authors.lastname: Cabana
authors.affiliation: †Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
authors.forename: John
authors.initials: J
authors.lastname: Kerr
authors.affiliation: †Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
authors.forename: Robert
authors.initials: R
authors.lastname: Kostecki