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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Abnormally Low Activation Energy in Cubic Na3SbS4 Superionic Conductor

Inorganic Na-ion superionic conductors play a vital role in all-solid-state Na batteries that operate at room temperature. Sodium thioantimonate (Na3SbS4), a popular sulfide-based solid electrolyte, has attracted serious attention due to its advantages of high ionic conductivity at room temperature and impressive chemical stability under ambient conditions. Much research detailing Na3SbS4 focused on its synthetic approaches and interfacial stability against Na metal, yet, there is limited information elucidating a fundamental understanding of the Na- ion diffusion mechanisms in Na3SbS4 with different crystal structures (e.g., tetragonal and cubic). Herein, we combine real-time electrochemical impedance measurements with theoretical simulations based on density functional theory and in situ quasi-elastic neutron scattering to study the Na-ion conductive properties of Na3SbS4 during its phase transition from a tetragonal to cubic structure. Although there is a slight change in the lattice parameters, the energy barrier for Na-ion diffusion in the tetragonal structure was determined to be much larger (5-10 times) than that in the cubic structure from both theoretical and experimental perspectives. The high degree of symmetry in cubic Na3SbS4 leads to less interatomic correlations between Na and S(Sb) atoms, a shorter jump distance (2.85 angstrom), and a larger diffusion coefficient. This research provides insight into understanding the Na-ion diffusion in solid electrolytes with phase transitions and provides fundamental guidance for designing novel solid-state Na-ion conductors.

Zhang, Qian↗
DOE OSTI2024

A family of dual-anion-based sodium superionic conductors for all-solid-state sodium-ion batteries

The sodium (Na) superionic conductor is a key component that could revolutionize the energy density and safety of conventional Na-ion batteries. However, existing Na superionic conductors are primarily based on a single-anion framework, each presenting inherent advantages and disadvantages. Here we introduce a family of amorphous Na-ion conductors (Na 2 O 2 –MCl y , M = Hf, Zr and Ta) based on the dual-anion framework of oxychloride. Benefiting from a dual-anion chemistry and with the resulting distinctive structures, Na 2 O 2 –MCl y electrolytes exhibit room-temperature ionic conductivities up to 2.0 mS cm -1 , wide electrochemical stability windows and desirable mechanical properties. All-solid-state Na-ion batteries incorporating amorphous Na 2 O 2 –HfCl 4 electrolyte and a Na 0.85 Mn 0.5 Ni 0.4 Fe 0.1 O 2 cathode exhibit a superior rate capability and long-term cycle stability, with 78% capacity retention after 700 cycles under 0.2 C (1C = 120 mA g -1 ) at room temperature. The discoveries in this work could trigger a new wave of enthusiasm for exploring new superionic conductors beyond those based on a single-anion framework.

25 ENERGY STORAGE↗
DOE OSTI2023

Morphodynamics of dendrite growth in alumina based all solid-state sodium metal batteries

All solid-state batteries (ASSBs) with ceramic electrolytes and alkali metal anodes are a potential future energy storage technology for vehicle electrification and smart grids. However, uncontrollable dendrite growth toward ultimate short circuiting in solid electrolytes (SEs) has become a serious concern in the design of long-cycle, safe ASSBs, and the underlying mechanism has remained unclear. Here through multiscale imaging and morphodynamic tracking we show that Na dendrites grow in β''-Al 2 O 3 SEs through an alternating sequence of Na deposition and crack propagation. Atomic-scale imaging evidenced that electrochemical cycling causes massive delamination cracking along the Na + conduction planes, accompanied by the closure of neighboring conduction channels. In situ SEM observations revealed a dynamic interplay between Na deposition and crack propagation: Na deposition accumulates mechanical stress that induces cracking; cracking releases the local stress, which promotes further Na deposition. Thus, Na deposition and cracking alternatingly proceed until short circuits take place. A multiscale phase-field model is developed to recapitulate the morphodynamics of Na dendrite growth, predicting the tree-like fractal morphology of the growing dendrites. Importantly, our findings suggest that decoupling between Na deposition and cracking represents an important route to mitigate uncontrollable dendrite growth in ASSBs.

25 ENERGY STORAGE↗
DOE OSTI2021

Antiphase boundary migration as a diffusion mechanism in a P3 sodium layered oxide

The electrode materials of Na-ion batteries must exhibit fast ion transport, a property that is often negatively impacted when mobile cations order. Many layered Na (and K) intercalation compounds adopt the P3 crystal structure, which tends to stabilize cation-vacancy orderings over a wide range of Na concentrations. The ordered phases have been predicted to consist of domains that are periodically separated by antiphase boundaries (APBs) to accommodate variations in Na concentration. The mechanisms and rates with which Na diffuses within such ordered phases of P3 are not understood. We have conducted a first-principles study of Na diffusion in the P3 structure, using Na x CoO 2 as a model system. We find that most simple nearest-neighbor hops in Na-vacancy ordered phases in P3 result in unstable configurations and are therefore forbidden. We identify an alternative mechanism of Na transport that is mediated by APB migration via the formation and expansion of kinks along domain boundaries. The limiting kinetic barriers for this mechanism are quite low (0.03 to 0.30 eV). Vacancy defects are not required, and furthermore have formation energies that are higher than those of the APB kink defects. Furthermore, our results suggest that APB migration is a fundamental diffusion mechanism in the P3 structure.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Inelastic relaxation processes in amorphous sodium silicates

During fracture amorphous oxides exhibit irreversible processes, including inelastic and nonrecoverable relaxation effects in the process zone surrounding the crack tip. Here, classical molecular dynamics simulations were used with a reactive forcefield to evaluate inelastic relaxation processes in five amorphous sodium silicate compositions. Overall, the 20% Na 2 O-SiO 2 (NS20) composition exhibited the most inelastic relaxation, followed by the 15% Na 2 O-SiO 2 (NS15) composition, the 25% Na 2 O-SiO 2 (NS25) composition, and finally the 10% (NS10) and 30% (NS30) Na 2 O-SiO 2 compositions. Coordination analysis of the Na + ions identified that during inelastic relaxation the Na+ ions were increasingly coordinated by nonbridging oxygens (NBOs) for the NS10 and NS15 compositions, which was supported by radial analysis of the O-Na-O bond angles surrounding the crack tip. Across the sodium silicate compositional range, two different inelastic relaxation mechanism were identified based on the amount of bridging oxygens (BOs) and NBOs in the Na+ ion coordination shell. At lower (NS10) and higher (NS30) sodium compositions, the entire structured relaxed toward the crack tip. In contrast at intermediate sodium concentrations (NS20) the Na + ion migrates toward the crack tip separately from the network structure. By developing a fundamental understanding of how modified silica systems respond to static stress fields, we will be able to predict how varying amorphous silicate systems exhibit slow crack growth.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Methanol Steam Reforming on Ru/m-ZrO 2 : Sodium Promotion of the CO 2 -Forming Pathway

Sodium (Na) promotion of Ru/m-ZrO 2 was investigated to elucidate how an alkali modification tunes selectivity in methanol steam reforming (MSR). H 2 -TPR/XANES/EXAFS show that Na increases surface basicity and strengthens Ru–O interactions, shifting RuO x reduction and H 2 spillover to a higher temperature. DRIFTS reveals Na-induced red shifts of the formate ν(CH) band and changes in OCO vibrational splitting, consistent with weakening of the formate C–H bond and an altered binding geometry. CO 2 -TPD confirms a monotonic shift toward stronger basic sites with increasing Na concentrations. Under MSR conditions, Na selectively increases CO2 concentration at the expense of CO. At ~80% conversion and 325 °C, CO 2 selectivity increases from 12.0% (unpromoted) to 16.2, 21.0, and 26.5% for 0.5, 1.0, and 1.8% Na, respectively; at ~300 °C and ~66–69% conversion, CO 2 selectivity increases from 8.6% to 23.7% at 1.8% Na. Transient MSR experiments further show earlier and larger H 2 evolution upon Na addition, corroborating the promotion of the dehydrogenation/decarbonylation route to CO 2 + H 2 . We propose that Na increases basicity and modifies the Ru–support interface to favor formate dehydrogenation/decarboxylation, thereby increasing the H 2 yield and lowering CO formation. Ru’s higher-energy, less occupied d-band stabilizes CO and oxygenated intermediates more strongly in the reforming environment, making the CO-forming pathway more resistant to suppression than on Pt.

CO2 selectivity↗
DOE OSTI2020

Materials Data on NaSn by Materials Project

NaSn crystallizes in the tetragonal I4_1/acd space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded in a 12-coordinate geometry to eight equivalent Sn atoms. There are a spread of Na–Sn bond distances ranging from 3.42–3.57 Å. In the second Na site, Na is bonded in a 6-coordinate geometry to six equivalent Sn atoms. There are four shorter (3.37 Å) and two longer (3.47 Å) Na–Sn bond lengths. Sn is bonded in a 10-coordinate geometry to seven Na and three equivalent Sn atoms. There are one shorter (3.03 Å) and two longer (3.05 Å) Sn–Sn bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na7Fe3O8 by Materials Project

Na7Fe3O8 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are seven inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted single-bond geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.88–2.92 Å. In the second Na1+ site, Na1+ is bonded in a 2-coordinate geometry to two O2- atoms. There are one shorter (2.20 Å) and one longer (2.56 Å) Na–O bond lengths. In the third Na1+ site, Na1+ is bonded in a distorted single-bond geometry to two O2- atoms. There are one shorter (1.58 Å) and one longer (2.83 Å) Na–O bond lengths. In the fourth Na1+ site, Na1+ is bonded in a 2-coordinate geometry to two O2- atoms. There are one shorter (2.39 Å) and one longer (2.45 Å) Na–O bond lengths. In the fifth Na1+ site, Na1+ is bonded in a distorted single-bond geometry to two O2- atoms. There are one shorter (1.90 Å) and one longer (2.69 Å) Na–O bond lengths. In the sixth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to one Fe3+ and three O2- atoms. The Na–Fe bond length is 2.42 Å. There are two shorter (2.18 Å) and one longer (2.40 Å) Na–O bond lengths. In the seventh Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.47–2.59 Å. There are three inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded in a 5-coordinate geometry to one Na1+ and four O2- atoms. There are a spread of Fe–O bond distances ranging from 1.86–2.31 Å. In the second Fe3+ site, Fe3+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Fe–O bond distances ranging from 1.59–1.99 Å. In the third Fe3+ site, Fe3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Fe–O bond distances ranging from 1.97–2.41 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+ and two Fe3+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one Fe3+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ and one Fe3+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+ and two Fe3+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two Fe3+ atoms. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+ and one Fe3+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one Fe3+ atom. In the eighth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Na1+ and one Fe3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na4WO5 by Materials Project

Na4WO5 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 1-coordinate geometry to one Na1+ and four O2- atoms. The Na–Na bond length is 2.57 Å. There are a spread of Na–O bond distances ranging from 2.10–2.82 Å. In the second Na1+ site, Na1+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 2.06–2.67 Å. In the third Na1+ site, Na1+ is bonded in a 12-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.35–2.85 Å. In the fourth Na1+ site, Na1+ is bonded in a 12-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.72–2.99 Å. In the fifth Na1+ site, Na1+ is bonded in a 12-coordinate geometry to two equivalent Na1+, two equivalent W6+, and eight O2- atoms. Both Na–W bond lengths are 2.61 Å. There are a spread of Na–O bond distances ranging from 2.46–2.79 Å. W6+ is bonded in a 1-coordinate geometry to one Na1+ and four O2- atoms. There are a spread of W–O bond distances ranging from 1.81–2.68 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ and two equivalent O2- atoms. There are one shorter (2.13 Å) and one longer (2.15 Å) O–O bond lengths. In the second O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one W6+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to five Na1+, two equivalent W6+, and two equivalent O2- atoms. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one W6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KNa22C2S9ClO42 by Materials Project

KNa22C2S9O42Cl crystallizes in the hexagonal P6_3/m space group. The structure is three-dimensional. K1+ is bonded to twelve O2- atoms to form KO12 cuboctahedra that share corners with six equivalent NaO6 octahedra, edges with six equivalent SO4 tetrahedra, and faces with two equivalent NaO6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are six shorter (2.96 Å) and six longer (3.19 Å) K–O bond lengths. There are six inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent KO12 cuboctahedra, corners with four equivalent SO4 tetrahedra, and edges with two equivalent NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.32–2.52 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with three equivalent NaO6 octahedra, corners with three SO4 tetrahedra, an edgeedge with one NaO6 octahedra, and an edgeedge with one SO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–75°. There are a spread of Na–O bond distances ranging from 2.33–2.64 Å. In the third Na1+ site, Na1+ is bonded in a 7-coordinate geometry to six O2- and one Cl1- atom. There are three shorter (2.45 Å) and three longer (2.72 Å) Na–O bond lengths. The Na–Cl bond length is 2.69 Å. In the fourth Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six SO4 tetrahedra, a faceface with one KO12 cuboctahedra, and a faceface with one NaO6 octahedra. There are three shorter (2.40 Å) and three longer (2.47 Å) Na–O bond lengths. In the fifth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to four O2- and one Cl1- atom. There are a spread of Na–O bond distances ranging from 2.29–2.53 Å. The Na–Cl bond length is 2.93 Å. In the sixth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.38–2.64 Å. C4+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All C–O bond lengths are 1.30 Å. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with four NaO6 octahedra and edges with two equivalent NaO6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of S–O bond distances ranging from 1.49–1.51 Å. In the second S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with five NaO6 octahedra and an edgeedge with one KO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 42–61°. There is two shorter (1.49 Å) and two longer (1.50 Å) S–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one S6+ atom. In the second O2- site, O2- is bonded to four Na1+ and one C4+ atom to form distorted ONa4C trigonal bipyramids that share a cornercorner with one ONa3S tetrahedra, a cornercorner with one ONa4C trigonal bipyramid, and edges with two equivalent ONa4C trigonal bipyramids. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, three Na1+, and one S6+ atom. In the fifth O2- site, O2- is bonded to three Na1+ and one S6+ atom to form distorted ONa3S tetrahedra that share a cornercorner with one ClNa5 trigonal bipyramid and corners with two equivalent ONa4C trigonal bipyramids. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, two Na1+, and one S6+ atom. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Na1+ and one S6+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ and one S6+ atom. Cl1- is bonded to five Na1+ atoms to form ClNa5 trigonal bipyramids that share corners with three equivalent ONa3S tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaHg by Materials Project

NaHg is alpha iridium vanadium-like structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded in a 8-coordinate geometry to eight equivalent Hg atoms. There are a spread of Na–Hg bond distances ranging from 3.23–3.29 Å. In the second Na site, Na is bonded in a 8-coordinate geometry to eight equivalent Hg atoms. There are a spread of Na–Hg bond distances ranging from 3.18–3.44 Å. Hg is bonded in a 8-coordinate geometry to eight Na atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na8Ga2O7 by Materials Project

Na8Ga2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are eight inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.46 Å. In the second Na1+ site, Na1+ is bonded to four O2- atoms to form NaO4 tetrahedra that share corners with two equivalent NaO6 octahedra, corners with three NaO4 tetrahedra, corners with four GaO4 tetrahedra, and an edgeedge with one NaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 29–92°. There are a spread of Na–O bond distances ranging from 2.28–2.47 Å. In the third Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share a cornercorner with one NaO6 octahedra, corners with two NaO4 tetrahedra, corners with four GaO4 tetrahedra, an edgeedge with one NaO6 octahedra, and edges with three NaO4 tetrahedra. The corner-sharing octahedral tilt angles are 93°. There are a spread of Na–O bond distances ranging from 2.27–2.45 Å. In the fourth Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with eight NaO4 tetrahedra, edges with two NaO4 tetrahedra, and edges with four GaO4 tetrahedra. The corner-sharing octahedral tilt angles are 22°. There are a spread of Na–O bond distances ranging from 2.47–2.63 Å. In the fifth Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with two equivalent NaO6 octahedra, corners with three GaO4 tetrahedra, corners with five NaO4 tetrahedra, an edgeedge with one NaO6 octahedra, an edgeedge with one NaO4 tetrahedra, and an edgeedge with one GaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 15–55°. There are a spread of Na–O bond distances ranging from 2.28–2.49 Å. In the sixth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.31–2.72 Å. In the seventh Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with three equivalent NaO6 octahedra, corners with two GaO4 tetrahedra, corners with four NaO4 tetrahedra, an edgeedge with one GaO4 tetrahedra, and edges with two NaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 23–42°. There are a spread of Na–O bond distances ranging from 2.23–2.54 Å. In the eighth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.35–2.74 Å. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share a cornercorner with one GaO4 tetrahedra, corners with six NaO4 tetrahedra, edges with two equivalent NaO6 octahedra, and edges with two NaO4 tetrahedra. There are a spread of Ga–O bond distances ranging from 1.87–1.93 Å. In the second Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share a cornercorner with one GaO4 tetrahedra, corners with seven NaO4 tetrahedra, and edges with two equivalent NaO6 octahedra. There are a spread of Ga–O bond distances ranging from 1.87–1.94 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded to five Na1+ and one Ga3+ atom to form a mixture of distorted edge and corner-sharing ONa5Ga octahedra. The corner-sharing octahedral tilt angles are 7°. In the second O2- site, O2- is bonded to five Na1+ and one Ga3+ atom to form a mixture of distorted edge and corner-sharing ONa5Ga octahedra. The corner-sharing octahedra tilt angles range from 7–66°. In the third O2- site, O2- is bonded in a 7-coordinate geometry to six Na1+ and one Ga3+ atom. In the fourth O2- site, O2- is bonded to five Na1+ and one Ga3+ atom to form a mixture of distorted edge and corner-sharing ONa5Ga octahedra. The corner-sharing octahedral tilt angles are 66°. In the fifth O2- site, O2- is bonded in a 6-coordinate geometry to four Na1+ and two Ga3+ atoms. In the sixth O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Ga3+ atom. In the seventh O2- site, O2- is bonded in a 7-coordinate geometry to six Na1+ and one Ga3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na3Bi by Materials Project

Na3Bi is Sodium arsenide structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded in a 1-coordinate geometry to four equivalent Bi atoms. There are one shorter (3.25 Å) and three longer (3.56 Å) Na–Bi bond lengths. In the second Na site, Na is bonded in a trigonal planar geometry to three equivalent Bi atoms. All Na–Bi bond lengths are 3.17 Å. Bi is bonded in a 5-coordinate geometry to eleven Na atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2BeO2 by Materials Project

Na2BeO2 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are eight inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.44–2.72 Å. In the second Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.26–2.43 Å. In the third Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.26–2.43 Å. In the fourth Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 trigonal pyramids that share a cornercorner with one BeO4 tetrahedra, corners with two equivalent NaO4 trigonal pyramids, and an edgeedge with one BeO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.30–2.44 Å. In the fifth Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 trigonal pyramids that share a cornercorner with one BeO4 tetrahedra, corners with two equivalent NaO4 trigonal pyramids, and an edgeedge with one BeO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.30–2.43 Å. In the sixth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.44–2.74 Å. In the seventh Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.26–2.36 Å. In the eighth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.27–2.36 Å. There are four inequivalent Be2+ sites. In the first Be2+ site, Be2+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of Be–O bond distances ranging from 1.53–1.59 Å. In the second Be2+ site, Be2+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of Be–O bond distances ranging from 1.53–1.59 Å. In the third Be2+ site, Be2+ is bonded to four O2- atoms to form BeO4 tetrahedra that share a cornercorner with one NaO4 trigonal pyramid, an edgeedge with one BeO4 tetrahedra, and an edgeedge with one NaO4 trigonal pyramid. There are a spread of Be–O bond distances ranging from 1.65–1.71 Å. In the fourth Be2+ site, Be2+ is bonded to four O2- atoms to form BeO4 tetrahedra that share a cornercorner with one NaO4 trigonal pyramid, an edgeedge with one BeO4 tetrahedra, and an edgeedge with one NaO4 trigonal pyramid. There are a spread of Be–O bond distances ranging from 1.65–1.71 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one Be2+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one Be2+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to four Na1+ and two Be2+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to four Na1+ and two Be2+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to three Na1+ and two Be2+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to three Na1+ and two Be2+ atoms. In the seventh O2- site, O2- is bonded in a 6-coordinate geometry to four Na1+ and two Be2+ atoms. In the eighth O2- site, O2- is bonded in a 6-coordinate geometry to four Na1+ and two Be2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na7(Cu6S5)2 by Materials Project

Na7Cu12S10 crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. there are eight inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing NaS6 octahedra. The corner-sharing octahedra tilt angles range from 40–43°. There are four shorter (2.94 Å) and two longer (2.99 Å) Na–S bond lengths. In the second Na1+ site, Na1+ is bonded to six S2- atoms to form a mixture of distorted edge, face, and corner-sharing NaS6 octahedra. The corner-sharing octahedra tilt angles range from 38–61°. There are a spread of Na–S bond distances ranging from 2.80–3.07 Å. In the third Na1+ site, Na1+ is bonded to six S2- atoms to form a mixture of distorted edge, face, and corner-sharing NaS6 octahedra. The corner-sharing octahedra tilt angles range from 38–62°. There are a spread of Na–S bond distances ranging from 2.91–3.09 Å. In the fourth Na1+ site, Na1+ is bonded to six S2- atoms to form a mixture of distorted edge, face, and corner-sharing NaS6 octahedra. The corner-sharing octahedra tilt angles range from 37–62°. There are a spread of Na–S bond distances ranging from 2.89–3.09 Å. In the fifth Na1+ site, Na1+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing NaS6 octahedra. The corner-sharing octahedra tilt angles range from 38–43°. All Na–S bond lengths are 2.94 Å. In the sixth Na1+ site, Na1+ is bonded to six S2- atoms to form a mixture of distorted edge, face, and corner-sharing NaS6 octahedra. The corner-sharing octahedra tilt angles range from 37–62°. There are a spread of Na–S bond distances ranging from 2.84–3.14 Å. In the seventh Na1+ site, Na1+ is bonded to six S2- atoms to form a mixture of distorted edge, face, and corner-sharing NaS6 octahedra. The corner-sharing octahedra tilt angles range from 38–61°. There are a spread of Na–S bond distances ranging from 2.79–3.07 Å. In the eighth Na1+ site, Na1+ is bonded to six S2- atoms to form a mixture of edge, face, and corner-sharing NaS6 octahedra. The corner-sharing octahedra tilt angles range from 38–62°. There are a spread of Na–S bond distances ranging from 2.79–3.02 Å. There are twelve inequivalent Cu+1.08+ sites. In the first Cu+1.08+ site, Cu+1.08+ is bonded in a distorted trigonal planar geometry to three S2- atoms. There are one shorter (2.27 Å) and two longer (2.44 Å) Cu–S bond lengths. In the second Cu+1.08+ site, Cu+1.08+ is bonded in a trigonal planar geometry to three S2- atoms. There are two shorter (2.26 Å) and one longer (2.35 Å) Cu–S bond lengths. In the third Cu+1.08+ site, Cu+1.08+ is bonded in a distorted trigonal planar geometry to three S2- atoms. There are one shorter (2.30 Å) and two longer (2.40 Å) Cu–S bond lengths. In the fourth Cu+1.08+ site, Cu+1.08+ is bonded in a trigonal non-coplanar geometry to three S2- atoms. There are two shorter (2.31 Å) and one longer (2.35 Å) Cu–S bond lengths. In the fifth Cu+1.08+ site, Cu+1.08+ is bonded in a trigonal planar geometry to three S2- atoms. There are two shorter (2.29 Å) and one longer (2.33 Å) Cu–S bond lengths. In the sixth Cu+1.08+ site, Cu+1.08+ is bonded in a trigonal planar geometry to three S2- atoms. There are one shorter (2.27 Å) and two longer (2.32 Å) Cu–S bond lengths. In the seventh Cu+1.08+ site, Cu+1.08+ is bonded in a trigonal planar geometry to three S2- atoms. There are two shorter (2.31 Å) and one longer (2.32 Å) Cu–S bond lengths. In the eighth Cu+1.08+ site, Cu+1.08+ is bonded in a distorted trigonal planar geometry to three S2- atoms. There are one shorter (2.30 Å) and two longer (2.42 Å) Cu–S bond lengths. In the ninth Cu+1.08+ site, Cu+1.08+ is bonded in a trigonal planar geometry to three S2- atoms. There are two shorter (2.24 Å) and one longer (2.40 Å) Cu–S bond lengths. In the tenth Cu+1.08+ site, Cu+1.08+ is bonded in a distorted trigonal non-coplanar geometry to three S2- atoms. There are one shorter (2.26 Å) and two longer (2.42 Å) Cu–S bond lengths. In the eleventh Cu+1.08+ site, Cu+1.08+ is bonded in a trigonal planar geometry to three S2- atoms. There are two shorter (2.28 Å) and one longer (2.30 Å) Cu–S bond lengths. In the twelfth Cu+1.08+ site, Cu+1.08+ is bonded in a trigonal planar geometry to three S2- atoms. There are one shorter (2.32 Å) and two longer (2.33 Å) Cu–S bond lengths. There are ten inequivalent S2- sites. In the first S2- site, S2- is bonded in a 9-coordinate geometry to three Na1+ and six Cu+1.08+ atoms. In the second S2- site, S2- is bonded in a 7-coordinate geometry to four Na1+ and three Cu+1.08+ atoms. In the third S2- site, S2- is bonded in a 8-coordinate geometry to five Na1+ and three Cu+1.08+ atoms. In the fourth S2- site, S2- is bonded in a 8-coordinate geometry to five Na1+ and three Cu+1.08+ atoms. In the fifth S2- site, S2- is bonded in a 7-coordinate geometry to four Na1+ and three Cu+1.08+ atoms. In the sixth S2- site, S2- is bonded in a 9-coordinate geometry to three Na1+ and six Cu+1.08+ atoms. In the seventh S2- site, S2- is bonded in a 8-coordinate geometry to five Na1+ and three Cu+1.08+ atoms. In the eighth S2- site, S2- is bonded in a 7-coordinate geometry to four Na1+ and three Cu+1.08+ atoms. In the ninth S2- site, S2- is bonded in a 7-coordinate geometry to four Na1+ and three Cu+1.08+ atoms. In the tenth S2- site, S2- is bonded in a 8-coordinate geometry to five Na1+ and three Cu+1.08+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na7Au5S6 by Materials Project

Na7Au5S6 crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to four equivalent Au1+ and four S2- atoms to form NaAu4S4 hexagonal bipyramids that share corners with four equivalent NaAu4S4 hexagonal bipyramids, edges with two equivalent NaAu3S4 pentagonal bipyramids, and faces with two equivalent NaAu3S4 pentagonal bipyramids. There are two shorter (3.18 Å) and two longer (3.23 Å) Na–Au bond lengths. There are two shorter (2.87 Å) and two longer (2.95 Å) Na–S bond lengths. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to two Au1+ and four S2- atoms. There are one shorter (3.27 Å) and one longer (3.32 Å) Na–Au bond lengths. There are a spread of Na–S bond distances ranging from 2.80–2.97 Å. In the third Na1+ site, Na1+ is bonded to three Au1+ and four S2- atoms to form distorted NaAu3S4 pentagonal bipyramids that share corners with two equivalent SNa6Au pentagonal bipyramids, corners with three equivalent NaAu3S4 pentagonal bipyramids, an edgeedge with one NaAu4S4 hexagonal bipyramid, and a faceface with one NaAu4S4 hexagonal bipyramid. There are one shorter (3.13 Å) and two longer (3.25 Å) Na–Au bond lengths. There are a spread of Na–S bond distances ranging from 2.84–2.90 Å. In the fourth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to two Au1+ and four S2- atoms. There are one shorter (3.08 Å) and one longer (3.16 Å) Na–Au bond lengths. There are a spread of Na–S bond distances ranging from 2.89–2.98 Å. There are three inequivalent Au1+ sites. In the first Au1+ site, Au1+ is bonded in a 5-coordinate geometry to three Na1+ and two S2- atoms. Both Au–S bond lengths are 2.33 Å. In the second Au1+ site, Au1+ is bonded in a 5-coordinate geometry to three Na1+ and two S2- atoms. There are one shorter (2.33 Å) and one longer (2.34 Å) Au–S bond lengths. In the third Au1+ site, Au1+ is bonded in a distorted body-centered cubic geometry to six Na1+ and two equivalent S2- atoms. Both Au–S bond lengths are 2.34 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded to six Na1+ and one Au1+ atom to form distorted SNa6Au pentagonal bipyramids that share corners with two equivalent NaAu3S4 pentagonal bipyramids, corners with three equivalent SNa6Au pentagonal bipyramids, and edges with three equivalent SNa6Au pentagonal bipyramids. In the second S2- site, S2- is bonded in a 6-coordinate geometry to four Na1+ and two Au1+ atoms. In the third S2- site, S2- is bonded in a 6-coordinate geometry to four Na1+ and two Au1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na10CaSn12 by Materials Project

Na10CaSn12 crystallizes in the cubic I-43m space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded to four equivalent Sn atoms to form corner-sharing NaSn4 tetrahedra. All Na–Sn bond lengths are 3.24 Å. In the second Na site, Na is bonded in a 9-coordinate geometry to nine equivalent Sn atoms. There are three shorter (3.46 Å) and six longer (3.55 Å) Na–Sn bond lengths. Ca is bonded in a 12-coordinate geometry to twelve equivalent Sn atoms. All Ca–Sn bond lengths are 3.48 Å. Sn is bonded in a 9-coordinate geometry to five Na, one Ca, and three equivalent Sn atoms. There are one shorter (2.92 Å) and two longer (3.01 Å) Sn–Sn bond lengths.

36 MATERIALS SCIENCE↗