TY - JOUR
T1 - Reaction thermochemistry of metal sulfides with GGA and GGA+U calculations
AU - Yu, Yang
AU - Aykol, Muratahan
AU - Wolverton, C.
N1 - Publisher Copyright:
© 2015 American Physical Society.
PY - 2015/11/9
Y1 - 2015/11/9
N2 - Sulfurization reaction energies of 24 metal sulfide (M-S) systems including M= Li, Na, K, Mg, Ca, Sr, Ba, Zn, Al, Ti, Mn, Fe, Co, Ni, Cu, Mo, Rh, Pd, Ir, Pt, La, Ce, Th, and U are evaluated using generalized gradient approximation (GGA) and GGA+U calculations. Our results indicate that unlike metal oxides and halides, GGA reaction energy predictions can be improved consistently only if separate energy corrections are used for S in sulfide anion (S2-) and disulfide anion (S22-) because of the existence of covalent -S-S- bonds in the latter anion. Enumerating all possible sulfurization reactions between pairs of d- and f-block metal sulfides within each M-S system, we predict effective U values for GGA+U thermochemistry and confidence intervals for these U values. We find that applying U on the d or f orbitals of these nonsimple metal ions consistently improves GGA reaction energy predictions for most of these systems, except for the reactions where the reaction energy is insensitive to U applied to the metal M, and only the S anions perform the redox activity (i.e., change the nominal oxidation state). We show that GGA+U calculations with the predicted U values and anion-dependent systematic energy corrections provide a significant improvement over standard, uncorrected GGA in predicting cell voltages of a variety of M-S based battery systems including Li/FeS2, Li/TiS2, Li/Mo6S8, and Mg/Mo6S8.
AB - Sulfurization reaction energies of 24 metal sulfide (M-S) systems including M= Li, Na, K, Mg, Ca, Sr, Ba, Zn, Al, Ti, Mn, Fe, Co, Ni, Cu, Mo, Rh, Pd, Ir, Pt, La, Ce, Th, and U are evaluated using generalized gradient approximation (GGA) and GGA+U calculations. Our results indicate that unlike metal oxides and halides, GGA reaction energy predictions can be improved consistently only if separate energy corrections are used for S in sulfide anion (S2-) and disulfide anion (S22-) because of the existence of covalent -S-S- bonds in the latter anion. Enumerating all possible sulfurization reactions between pairs of d- and f-block metal sulfides within each M-S system, we predict effective U values for GGA+U thermochemistry and confidence intervals for these U values. We find that applying U on the d or f orbitals of these nonsimple metal ions consistently improves GGA reaction energy predictions for most of these systems, except for the reactions where the reaction energy is insensitive to U applied to the metal M, and only the S anions perform the redox activity (i.e., change the nominal oxidation state). We show that GGA+U calculations with the predicted U values and anion-dependent systematic energy corrections provide a significant improvement over standard, uncorrected GGA in predicting cell voltages of a variety of M-S based battery systems including Li/FeS2, Li/TiS2, Li/Mo6S8, and Mg/Mo6S8.
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U2 - 10.1103/PhysRevB.92.195118
DO - 10.1103/PhysRevB.92.195118
M3 - Article
AN - SCOPUS:84947093673
SN - 1098-0121
VL - 92
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 19
M1 - 195118
ER -