TY - JOUR
T1 - Identification of dopant site and its effect on electrochemical activity in Mn-doped lithium titanate
AU - Singh, Harishchandra
AU - Topsakal, Mehmet
AU - Attenkofer, Klaus
AU - Wolf, Tamar
AU - Leskes, Michal
AU - Duan, Yandong
AU - Wang, Feng
AU - Vinson, John
AU - Lu, Deyu
AU - Frenkel, Anatoly
N1 - A.I.F. and H.S. acknowledge support by National Science Foundation (NSF) Grant No. DMR-1701747. This research used the 8-ID (ISS) beamline of the National Synchrotron Light Source, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-AC02-98CH10886. Operations at the Beamline BL2-2 in SSRL were supported in part by the Synchrotron Catalysis Consortium (US Department of Energy, Office of Basic Energy Sciences, Grant No. DE-SC0012335). The x-ray absorption spectra calculations used resources of the National Energy Research Scientific Computing Center (NERSC), a US Department of Energy Office of Science User Facility operated under Contract No. DE-AC02-05CH11231. Research was carried out at the Center for Functional Nanomaterials and the Scientific Data and Computing Center, a component of the Computational Science Initiative, which are supported by the US Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-SC0012704. M.T. was supported by the LDRD grant at the Brookhaven National Laboratory (Grant No. 16–039). Efforts on electrochemical tests were supported by the Center for Mesoscale Transport Properties, an Energy Frontier Research Center supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, under Award No. DE-SC0012673. H.S. and M.T. contributed equally to this work.
PY - 2018/12/20
Y1 - 2018/12/20
N2 - Doped metal oxide materials are commonly used for applications in energy storage and conversion, such as batteries and solid oxide fuel cells. The knowledge of the electronic properties of dopants and their local environment is essential for understanding the effects of doping on the electrochemical properties. Using a combination of x-ray absorption near-edge structure spectroscopy (XANES) experiment and theoretical modeling we demonstrate that in the dilute (1 at. %) Mn-doped lithium titanate (Li4/3Ti5/3O4, or LTO) the dopant Mn2+ ions reside on tetrahedral (8a) sites. First-principles Mn K-edge XANES calculations revealed the spectral signature of the tetrahedrally coordinated Mn as a sharp peak in the middle of the absorption edge rise, caused by the 1s -> 4p transition, and it is important to include the effective electron-core hole Coulomb interaction in order to calculate the intenisty of this peak accurately. This dopant location can explain the impedance of Li migration through the LTO lattice during the charge-discharge process, and, as a result, the observed remarkable 20% decrease in electrochemical capacity of the 1% Mn-doped LTO compared to pristine LTO.
AB - Doped metal oxide materials are commonly used for applications in energy storage and conversion, such as batteries and solid oxide fuel cells. The knowledge of the electronic properties of dopants and their local environment is essential for understanding the effects of doping on the electrochemical properties. Using a combination of x-ray absorption near-edge structure spectroscopy (XANES) experiment and theoretical modeling we demonstrate that in the dilute (1 at. %) Mn-doped lithium titanate (Li4/3Ti5/3O4, or LTO) the dopant Mn2+ ions reside on tetrahedral (8a) sites. First-principles Mn K-edge XANES calculations revealed the spectral signature of the tetrahedrally coordinated Mn as a sharp peak in the middle of the absorption edge rise, caused by the 1s -> 4p transition, and it is important to include the effective electron-core hole Coulomb interaction in order to calculate the intenisty of this peak accurately. This dopant location can explain the impedance of Li migration through the LTO lattice during the charge-discharge process, and, as a result, the observed remarkable 20% decrease in electrochemical capacity of the 1% Mn-doped LTO compared to pristine LTO.
UR - http://www.scopus.com/inward/record.url?scp=85060648969&partnerID=8YFLogxK
U2 - 10.1103/PhysRevMaterials.2.125403
DO - 10.1103/PhysRevMaterials.2.125403
M3 - مقالة
SN - 2475-9953
VL - 2
JO - Physical Review Materials
JF - Physical Review Materials
IS - 12
M1 - 125403
ER -