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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Electrochemical Formation of Li-M-(M')-Si Phases Using Multivalent Electrolyte Salt Additives

Lithium-rich silicides (Li 15 Si 4 ), formed during the electrochemical lithiation of silicon, show high reactivity with electrolyte components that contribute to capacity decay, formal lithium loss, and low coulombic efficiency. Recently, the reactivity of lithium silicides was found to be suppressed by substituting a multivalent cation (i.e. Mg, Ca) for lithium that results in the room temperature formation of a ternary Li-M-Si phase. In this study, we explored a range of multivalent electrolyte salt additives (M = Ni, Cu, La, Ce, Sr, Ba, and Ca-Mg mixed salt) in a lithium-ion cell configuration and identified a room temperature electrochemical route to the formation of new ternary and quaternary lithium silicides. Using this method, both nickel and copper salts were found to plate onto the silicon electrode surface upon lithiation. Further, based on refined synchrotron XRD data, multivalent cations with an ionic radius similar to Na (~1.03 Å) or smaller can be inserted electrochemically into a formally cation-deficient Li 15 Si 4 host lattice to form new ternary (or quartenary) phases. The electrochemical synthesis of a new quaternary Li-M-M’-Si phase represents a facile route to preparing and scaling materials isostructural to the Heusler phase and electron-precise Li 14 MgSi 4 phase that results in enhanced cycling and calendar life performance.

25 ENERGY STORAGE↗
DOE OSTI2021

Precipitation of low-temperature disordered dolomite induced by extracellular polymeric substances of methanogenic Archaea Methanosarcina barkeri : Implications for sedimentary dolomite formation

Abstract A correlation between methanogenesis and dolomite formation has been reported; however, the mechanism underlying this association is not fully understood. In this study, we conducted forced carbonate precipitation experiments at room temperature in calcite-seeded Ca/Mg carbonate solutions containing either purified non-living biomass or bound extracellular polymeric substances (EPS) of the methanogen Methanosarcina barkeri. Purified non-living biomass and bound EPS was used so as to avoid the possible influence of the complex components of the growing microbial culture on carbonate crystallization. Our results demonstrated that non-living biomass of M. Barkeri can enhance the Mg incorporation into calcitic structure and induce the crystallization of disordered dolomite. In the presence of ~113 mg L–1 of non-living biomass, disordered dolomite with ~41 and 45 mol% of MgCO3 was precipitated in solutions with initial Mg:Ca ratios of 5:1 and 8:1, respectively. A systematic increase in the MgCO3 contents of the precipitated Ca-Mg carbonates was also observed with the increased non-living biomass concentration. Bound EPS was shown to be the component of non-living biomass that catalyzed the precipitation of disordered dolomite. At only ~25 mg L–1 of bound EPS, disordered dolomite with ~47 and 48 mol% of MgCO3 was precipitated in solutions with initial Mg:Ca ratios of 5:1 and 8:1, respectively. We propose that adsorption of bound EPS to growing carbonate surfaces through hydrogen bonding is the key to catalyzing disordered dolomite crystallization, and that this mechanism is also applicable to natural EPS-induced dolomite formation. This study provides significant insight into the formation mechanism of microbial-induced dolomite with high δ13C values.

Geochemistry & Geophysics↗
DOE OSTI2020

Materials Data on CaMg2 by Materials Project

Mg2Ca is Hexagonal Laves structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ca is bonded in a 12-coordinate geometry to four equivalent Ca and twelve Mg atoms. There are one shorter (3.76 Å) and three longer (3.82 Å) Ca–Ca bond lengths. There are a spread of Ca–Mg bond distances ranging from 3.60–3.67 Å. There are two inequivalent Mg sites. In the first Mg site, Mg is bonded to six equivalent Ca and six equivalent Mg atoms to form a mixture of corner, edge, and face-sharing MgCa6Mg6 cuboctahedra. All Mg–Mg bond lengths are 3.10 Å. In the second Mg site, Mg is bonded to six equivalent Ca and six Mg atoms to form a mixture of corner, edge, and face-sharing MgCa6Mg6 cuboctahedra. There are two shorter (3.09 Å) and two longer (3.17 Å) Mg–Mg bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaMg by Materials Project

MgCa crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Ca is bonded to six equivalent Ca and six equivalent Mg atoms to form a mixture of distorted corner, edge, and face-sharing CaCa6Mg6 cuboctahedra. All Ca–Ca bond lengths are 3.66 Å. All Ca–Mg bond lengths are 3.53 Å. Mg is bonded in a distorted hexagonal planar geometry to six equivalent Ca atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca2Mg by Materials Project

Ca2Mg is Molybdenite structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is two-dimensional and consists of two Ca2Mg sheets oriented in the (0, 0, 1) direction. Ca is bonded to three equivalent Mg atoms to form a mixture of distorted corner and face-sharing CaMg3 cuboctahedra. All Ca–Mg bond lengths are 3.53 Å. Mg is bonded in a 6-coordinate geometry to six equivalent Ca atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca2Mg by Materials Project

Ca2Mg crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are three inequivalent Ca sites. In the first Ca site, Ca is bonded to twelve Ca atoms to form a mixture of corner, edge, and face-sharing CaCa12 cuboctahedra. There are six shorter (3.79 Å) and six longer (3.88 Å) Ca–Ca bond lengths. In the second Ca site, Ca is bonded to three equivalent Ca and three equivalent Mg atoms to form distorted CaCa3Mg3 cuboctahedra that share corners with eighteen CaCa12 cuboctahedra, edges with twelve CaCa12 cuboctahedra, and faces with two CaCa3Mg3 cuboctahedra. All Ca–Mg bond lengths are 3.50 Å. In the third Ca site, Ca is bonded to six equivalent Mg atoms to form distorted CaMg6 cuboctahedra that share corners with twelve equivalent CaCa3Mg3 cuboctahedra, edges with six equivalent CaMg6 cuboctahedra, and faces with two equivalent CaCa3Mg3 cuboctahedra. All Ca–Mg bond lengths are 3.56 Å. Mg is bonded in a 6-coordinate geometry to six Ca atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca5Mg by Materials Project

Ca5Mg crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are five inequivalent Ca sites. In the first Ca site, Ca is bonded to ten Ca and two equivalent Mg atoms to form distorted CaCa10Mg2 cuboctahedra that share corners with twelve CaCa10Mg2 cuboctahedra, edges with nine CaCa8Mg2 cuboctahedra, and faces with fourteen CaCa10Mg2 cuboctahedra. There are a spread of Ca–Ca bond distances ranging from 3.75–4.00 Å. Both Ca–Mg bond lengths are 3.65 Å. In the second Ca site, Ca is bonded in a 11-coordinate geometry to nine Ca and two equivalent Mg atoms. There are a spread of Ca–Ca bond distances ranging from 3.59–3.83 Å. Both Ca–Mg bond lengths are 3.75 Å. In the third Ca site, Ca is bonded to eight Ca and two equivalent Mg atoms to form distorted CaCa8Mg2 cuboctahedra that share corners with fourteen CaCa8Mg2 cuboctahedra, edges with five CaCa10Mg2 cuboctahedra, and faces with fourteen CaCa10Mg2 cuboctahedra. There are a spread of Ca–Ca bond distances ranging from 3.83–3.99 Å. Both Ca–Mg bond lengths are 3.64 Å. In the fourth Ca site, Ca is bonded to eleven Ca and one Mg atom to form a mixture of distorted corner, edge, and face-sharing CaCa11Mg cuboctahedra. There are two shorter (3.82 Å) and two longer (3.84 Å) Ca–Ca bond lengths. The Ca–Mg bond length is 3.71 Å. In the fifth Ca site, Ca is bonded to ten Ca and two equivalent Mg atoms to form distorted CaCa10Mg2 cuboctahedra that share corners with fourteen CaCa8Mg2 cuboctahedra, edges with nine CaCa10Mg2 cuboctahedra, and faces with thirteen CaCa10Mg2 cuboctahedra. Both Ca–Ca bond lengths are 3.82 Å. Both Ca–Mg bond lengths are 3.69 Å. Mg is bonded in a 9-coordinate geometry to nine Ca atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaMg3 by Materials Project

Mg3Ca is beta-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Ca is bonded to six equivalent Ca and six equivalent Mg atoms to form CaCa6Mg6 cuboctahedra that share corners with six equivalent CaCa6Mg6 cuboctahedra, corners with twelve equivalent MgMg12 cuboctahedra, edges with six equivalent CaCa6Mg6 cuboctahedra, edges with twelve equivalent MgCa3Mg9 cuboctahedra, faces with six equivalent CaCa6Mg6 cuboctahedra, and faces with fourteen MgMg12 cuboctahedra. All Ca–Ca bond lengths are 3.41 Å. All Ca–Mg bond lengths are 3.49 Å. There are two inequivalent Mg sites. In the first Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with six equivalent MgMg12 cuboctahedra, corners with twelve equivalent CaCa6Mg6 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, faces with two equivalent CaCa6Mg6 cuboctahedra, and faces with eighteen MgMg12 cuboctahedra. There are six shorter (3.23 Å) and six longer (3.41 Å) Mg–Mg bond lengths. In the second Mg site, Mg is bonded to three equivalent Ca and nine Mg atoms to form MgCa3Mg9 cuboctahedra that share corners with eighteen equivalent MgCa3Mg9 cuboctahedra, edges with six equivalent CaCa6Mg6 cuboctahedra, edges with twelve MgMg12 cuboctahedra, faces with six equivalent CaCa6Mg6 cuboctahedra, and faces with fourteen MgMg12 cuboctahedra. All Mg–Mg bond lengths are 3.41 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaMg2 by Materials Project

Mg2Ca crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ca is bonded to two equivalent Ca and ten equivalent Mg atoms to form CaCa2Mg10 cuboctahedra that share corners with six equivalent CaCa2Mg10 cuboctahedra, corners with twelve equivalent MgCa5Mg7 cuboctahedra, edges with eight equivalent MgCa5Mg7 cuboctahedra, edges with ten equivalent CaCa2Mg10 cuboctahedra, faces with four equivalent CaCa2Mg10 cuboctahedra, and faces with sixteen equivalent MgCa5Mg7 cuboctahedra. Both Ca–Ca bond lengths are 3.41 Å. There are a spread of Ca–Mg bond distances ranging from 3.36–3.53 Å. Mg is bonded to five equivalent Ca and seven equivalent Mg atoms to form distorted MgCa5Mg7 cuboctahedra that share corners with six equivalent CaCa2Mg10 cuboctahedra, corners with twelve equivalent MgCa5Mg7 cuboctahedra, edges with four equivalent CaCa2Mg10 cuboctahedra, edges with fourteen equivalent MgCa5Mg7 cuboctahedra, faces with eight equivalent CaCa2Mg10 cuboctahedra, and faces with twelve equivalent MgCa5Mg7 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.38–3.47 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaMg by Materials Project

MgCa crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Ca is bonded to six equivalent Ca and six equivalent Mg atoms to form a mixture of distorted corner, edge, and face-sharing CaCa6Mg6 cuboctahedra. All Ca–Ca bond lengths are 3.67 Å. All Ca–Mg bond lengths are 3.52 Å. Mg is bonded in a 6-coordinate geometry to six equivalent Ca atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca2Mg by Materials Project

Ca2Mg crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent Ca sites. In the first Ca site, Ca is bonded to nine Ca and three Mg atoms to form distorted CaCa9Mg3 cuboctahedra that share corners with twelve CaCa9Mg3 cuboctahedra, edges with five CaCa7Mg5 cuboctahedra, and faces with ten CaCa9Mg3 cuboctahedra. There are a spread of Ca–Ca bond distances ranging from 3.71–3.84 Å. There are two shorter (3.51 Å) and one longer (3.71 Å) Ca–Mg bond lengths. In the second Ca site, Ca is bonded to seven Ca and five Mg atoms to form a mixture of distorted edge, face, and corner-sharing CaCa7Mg5 cuboctahedra. There are two shorter (3.70 Å) and three longer (3.71 Å) Ca–Ca bond lengths. There are a spread of Ca–Mg bond distances ranging from 3.53–3.79 Å. In the third Ca site, Ca is bonded in a 12-coordinate geometry to six Ca and three Mg atoms. Both Ca–Ca bond lengths are 3.81 Å. There are one shorter (3.40 Å) and two longer (3.56 Å) Ca–Mg bond lengths. In the fourth Ca site, Ca is bonded to eight Ca and four Mg atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with six equivalent CaCa8Mg4 cuboctahedra, edges with six CaCa9Mg3 cuboctahedra, and faces with eleven CaCa9Mg3 cuboctahedra. Both Ca–Ca bond lengths are 3.71 Å. There are two shorter (3.66 Å) and two longer (3.73 Å) Ca–Mg bond lengths. There are two inequivalent Mg sites. In the first Mg site, Mg is bonded in a 8-coordinate geometry to eight Ca atoms. In the second Mg site, Mg is bonded in a 7-coordinate geometry to seven Ca atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca2Mg by Materials Project

Ca2Mg crystallizes in the trigonal R32 space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded to eight Ca and four equivalent Mg atoms to form a mixture of face, edge, and corner-sharing CaCa8Mg4 cuboctahedra. There are a spread of Ca–Ca bond distances ranging from 3.62–3.71 Å. There are two shorter (3.68 Å) and two longer (3.71 Å) Ca–Mg bond lengths. In the second Ca site, Ca is bonded to six equivalent Ca and six equivalent Mg atoms to form CaCa6Mg6 cuboctahedra that share corners with six equivalent CaCa6Mg6 cuboctahedra, edges with eighteen CaCa8Mg4 cuboctahedra, and faces with twelve equivalent CaCa8Mg4 cuboctahedra. All Ca–Mg bond lengths are 3.68 Å. Mg is bonded in a 9-coordinate geometry to nine Ca atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaMg2 by Materials Project

Mg2Ca is Bergman Structure: Mg32(Al,Zn)49 Bergman-derived structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ca is bonded to three equivalent Ca and nine Mg atoms to form distorted CaCa3Mg9 cuboctahedra that share corners with six equivalent CaCa3Mg9 cuboctahedra, corners with six equivalent MgCa5Mg7 cuboctahedra, edges with four equivalent CaCa3Mg9 cuboctahedra, edges with five equivalent MgCa5Mg7 cuboctahedra, faces with six equivalent CaCa3Mg9 cuboctahedra, and faces with eight equivalent MgCa5Mg7 cuboctahedra. There are two shorter (3.48 Å) and one longer (3.59 Å) Ca–Ca bond lengths. There are a spread of Ca–Mg bond distances ranging from 3.40–3.58 Å. There are two inequivalent Mg sites. In the first Mg site, Mg is bonded to five equivalent Ca and seven Mg atoms to form distorted MgCa5Mg7 cuboctahedra that share corners with six equivalent CaCa3Mg9 cuboctahedra, corners with six equivalent MgCa5Mg7 cuboctahedra, edges with five equivalent CaCa3Mg9 cuboctahedra, edges with six equivalent MgCa5Mg7 cuboctahedra, faces with five equivalent MgCa5Mg7 cuboctahedra, and faces with eight equivalent CaCa3Mg9 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.20–3.48 Å. In the second Mg site, Mg is bonded in a 11-coordinate geometry to four equivalent Ca and seven Mg atoms. There are two shorter (3.12 Å) and two longer (3.48 Å) Mg–Mg bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaMg2 by Materials Project

Mg2Ca crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ca is bonded to two equivalent Ca and ten Mg atoms to form distorted CaCa2Mg10 cuboctahedra that share corners with six equivalent CaCa2Mg10 cuboctahedra, corners with twelve MgCa6Mg6 cuboctahedra, edges with eight equivalent CaCa2Mg10 cuboctahedra, edges with ten MgCa6Mg6 cuboctahedra, faces with six equivalent CaCa2Mg10 cuboctahedra, and faces with fourteen MgCa6Mg6 cuboctahedra. Both Ca–Ca bond lengths are 3.47 Å. There are a spread of Ca–Mg bond distances ranging from 3.39–3.48 Å. There are two inequivalent Mg sites. In the first Mg site, Mg is bonded to six equivalent Ca and six Mg atoms to form distorted MgCa6Mg6 cuboctahedra that share corners with six equivalent CaCa2Mg10 cuboctahedra, corners with twelve MgCa6Mg6 cuboctahedra, edges with seven equivalent CaCa2Mg10 cuboctahedra, edges with eleven equivalent MgCa4Mg8 cuboctahedra, faces with six equivalent CaCa2Mg10 cuboctahedra, and faces with fourteen MgCa6Mg6 cuboctahedra. There are two shorter (3.32 Å) and four longer (3.47 Å) Mg–Mg bond lengths. In the second Mg site, Mg is bonded to four equivalent Ca and eight Mg atoms to form distorted MgCa4Mg8 cuboctahedra that share corners with six equivalent CaCa2Mg10 cuboctahedra, corners with twelve MgCa6Mg6 cuboctahedra, edges with three equivalent CaCa2Mg10 cuboctahedra, edges with fifteen MgCa6Mg6 cuboctahedra, faces with eight equivalent CaCa2Mg10 cuboctahedra, and faces with twelve MgCa6Mg6 cuboctahedra. All Mg–Mg bond lengths are 3.47 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaMg by Materials Project

MgCa is beta-prime cadmium gold structured and crystallizes in the orthorhombic Pmma space group. The structure is three-dimensional. Ca is bonded to four equivalent Ca and eight equivalent Mg atoms to form a mixture of distorted edge, face, and corner-sharing CaCa4Mg8 cuboctahedra. There are two shorter (3.58 Å) and two longer (3.67 Å) Ca–Ca bond lengths. There are a spread of Ca–Mg bond distances ranging from 3.41–3.57 Å. Mg is bonded in a 8-coordinate geometry to eight equivalent Ca atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaMg3 by Materials Project

Mg3Ca is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ca is bonded in a body-centered cubic geometry to fourteen Mg atoms. There are eight shorter (3.24 Å) and six longer (3.75 Å) Ca–Mg bond lengths. There are two inequivalent Mg sites. In the first Mg site, Mg is bonded in a 8-coordinate geometry to six equivalent Ca and eight equivalent Mg atoms. All Mg–Mg bond lengths are 3.24 Å. In the second Mg site, Mg is bonded in a body-centered cubic geometry to four equivalent Ca and four equivalent Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaMg2 by Materials Project

Mg2Ca crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ca is bonded in a 10-coordinate geometry to ten equivalent Mg atoms. There are eight shorter (3.44 Å) and two longer (3.57 Å) Ca–Mg bond lengths. Mg is bonded in a distorted q6 geometry to five equivalent Ca and four equivalent Mg atoms. All Mg–Mg bond lengths are 3.14 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaMg5 by Materials Project

CaMg5 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Ca is bonded to twelve Mg atoms to form CaMg12 cuboctahedra that share corners with eighteen equivalent MgCa3Mg9 cuboctahedra, edges with six equivalent CaMg12 cuboctahedra, faces with two equivalent CaMg12 cuboctahedra, and faces with six equivalent MgCa3Mg9 cuboctahedra. There are six shorter (3.29 Å) and six longer (3.39 Å) Ca–Mg bond lengths. There are two inequivalent Mg sites. In the first Mg site, Mg is bonded in a 12-coordinate geometry to two equivalent Ca and eight Mg atoms. There are four shorter (3.18 Å) and four longer (3.26 Å) Mg–Mg bond lengths. In the second Mg site, Mg is bonded to three equivalent Ca and nine Mg atoms to form MgCa3Mg9 cuboctahedra that share corners with nine equivalent CaMg12 cuboctahedra, corners with nine equivalent MgCa3Mg9 cuboctahedra, edges with six equivalent MgCa3Mg9 cuboctahedra, faces with three equivalent CaMg12 cuboctahedra, and faces with five equivalent MgCa3Mg9 cuboctahedra. All Mg–Mg bond lengths are 3.29 Å.

36 MATERIALS SCIENCE↗