steven kmiec - Academia.edu (original) (raw)
Papers by steven kmiec
Advanced energy materials, Jun 29, 2024
Chemistry of materials, May 29, 2024
Inorganic chemistry, May 6, 2024
The journal of physical chemistry. A/The journal of physical chemistry. A., Apr 25, 2024
Angewandte Chemie, Apr 16, 2024
Batteries & supercaps, Oct 13, 2022
The short-range order (SRO) structures of glasses in the Na4P2S 7-xOx, 0 ≤ x ≤ 7, series were inv... more The short-range order (SRO) structures of glasses in the Na4P2S 7-xOx, 0 ≤ x ≤ 7, series were investigated on samples prepared by planetary ball milling (PBM). Like other glasses prepared by PBM, the glassy nature of the prepared materials was confirmed by x-ray diffraction (XRD) showing that they were structurally amorphous and by differential scanning calorimetry (DSC) showing that each composition exhibited a reproducible glass transition temperature (Tg). The short-range order (SRO) structure of these glasses were determined using Raman, Fourier Transform Infrared (FT-IR), and 31 P Magic Angle Spinning NMR (MAS NMR) spectroscopies to investigate how oxygen and sulfur are bonded in the various SRO structural units that were found in these glasses. The three spectroscopic techniques gave further evidence that the resulting glasses were completely reacted from their polycrystalline starting materials Na2S, P2S5 and P2O5. It was found that significant disproportionation reactions occur in these compositions in which the original as batched and expected pyro-phosphate SRO units, P 1 = 2 Na/P, for x = 0 undergo a transformation to form ortho-phosphate (P 0 , 3 Na/P) and meta-phosphate (P 2 , 1 Na/P) SRO structures with increasing x such that there is a conservation of Na + charge, on average 2Na/P. In this nomenclature, the superscript describes the number of bridging sulfurs (BSs) and the number of Na per P plus one (arising from the P +5 valency) describing the number of non-bridging sulfurs (NBSs) on each of the SRO units. As seen in earlier work on other mixed oxy-sulfide (MOS) glass forming systems, the stronger Lewis base O = , compared to S = , is found to preferentially form bridging oxygen (BOs) in the form of P 2 SRO units by bonding to the stronger Lewis acid P +5 , compared to Na +. This leaves the weaker Lewis base S = to bond to the weaker Lewis acid, Na + in the form of non-bridging sulfurs (NBSs) on the charge compensation required P 0 groups. Using both charge balance and quantitative 31 P MAS NMR measurements, a complete composition map of all of the SRO structures present in these glasses has been created.
Batteries & Supercaps
Nature Communications
All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage.... more All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage. However, there are no commercialized ASSSBs yet, in part due to the lack of a low-cost, simple-to-fabricate solid electrolyte (SE) with electrochemical stability towards Na metal. In this work, we report a family of oxysulfide glass SEs (Na3PS4−xOx, where 0 < x ≤ 0.60) that not only exhibit the highest critical current density among all Na-ion conducting sulfide-based SEs, but also enable high-performance ambient-temperature sodium-sulfur batteries. By forming bridging oxygen units, the Na3PS4−xOx SEs undergo pressure-induced sintering at room temperature, resulting in a fully homogeneous glass structure with robust mechanical properties. Furthermore, the self-passivating solid electrolyte interphase at the Na|SE interface is critical for interface stabilization and reversible Na plating and stripping. The new structural and compositional design strategies presented here provide a ne...
ECS Meeting Abstracts, 2021
Solid-state batteries present many advantages over liquid electrolyte systems, enabling the use o... more Solid-state batteries present many advantages over liquid electrolyte systems, enabling the use of lithium metal anodes due to the non-flammable nature of the inorganic electrolyte. Glassy materials in particular are promising candidates as solid electrolytes due to their highly tunable properties, the absence of grain boundaries, and their ease of processability. The large compositional window of glassy materials allows for optimizing glass-forming ability and conductivity, while the lack of grain boundaries may be beneficial in preventing lithium dendrite formation. While lithium metaphosphate (LiPO3) has a low room temperature ionic conductivity (σ25°C = 1.6 ∙ 10-9 S/cm) that limits its use in solid-state batteries, oxides present similar processability and higher chemical and electrochemical stability than their higher conductivity sulfide analogues. LiPO3 was chosen for a preliminary investigation into the effects and challenges of decreasing electrolyte thickness due to its lo...
ACS Applied Materials & Interfaces, 2021
Glassy sulfide materials have been considered as promising candidates for solid-state electrolyte... more Glassy sulfide materials have been considered as promising candidates for solid-state electrolytes (SSEs) in lithium and sodium metal (LM and SM) batteries. While much of the current research on lithium glassy SSEs (GSSEs) has focused on the pure sulfide binary Li2S + P2S5 system, we have expanded these efforts by examining mixed-glass-former (MGF) compositions which have mixtures of glass formers, such as P and Si, which allow melt-quenching synthesis under ambient pressure and therefore the use of grain-boundary-free SSEs. We have doped these MGF compositions with oxygen to improve the chemical, electrochemical, and thermal properties of these glasses. In this work, we report on the short-range order (SRO), namely atomic-level, structures of Li2S + SiS2 + P2O5 MGF mixed oxy-sulfide glasses and, for the first time, study the critical current density (CCD) of these Si-doped oxy-sulfide GSSEs in LM symmetric cells. The samples were synthesized by planetary ball milling (PBM), and it was observed that a certain minimum milling time was necessary to achieve a final SRO structure. To address the short-circuiting lithium dendrite (LD) problems that were observed in these GSSEs, we demonstrate a simple and novel strategy for these Si-doped oxy-sulfide GSSEs to engineer the LM-GSSE interface by forming an in situ interlayer via heat treatment. Stable cycling to ∼1200 h at a capacity of 2 mAh·cm-2 per discharge/charge cycle under a current density of 1 mA·cm-2 is achieved. These results indicate that these MGF oxy-sulfide GSSEs combined with an optimized interfacial modification may find use in LM, and by extrapolation, SM, batteries.
All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage ... more All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage applications. To date, however, there are no commercialized ASSSBs due in part to the lack of a solid electrolyte (SE) that meets all of the requirements of low cost, facile fabrication, high Na+ conductivity, electrochemical stability, and is resistant to sodium metal dendrite penetration. In this work, we report a family of oxysulfide glass SEs (Na3PS4−xOx, where 0 < x ≤ 0.6) that combine the advantages of sulfides and oxides, we demonstrate stable electrochemical cycling of Na metal for hundreds of hours and the highest critical current density of 2.3 mA cm−2 among all Na-ion conducting sulfide-based SEs. These performance enhancements are found to be associated with the ability of the oxysulfide glass to undergo room temperature pressure induced amorphization that creates a fully homogeneous glass structure that has robust mechanics and substantial chemical and electrochemical sta...
Journal of Non-Crystalline Solids, 2021
During their operation, modern aircraft engine components are subjected to increasingly demanding... more During their operation, modern aircraft engine components are subjected to increasingly demanding operating conditions, especially the high pressure turbine (HPT) blades. Such conditions cause these parts to undergo different types of time-dependent degradation, one of which is creep. A model using the finite element method (FEM) was developed, in order to be able to predict the creep behaviour of HPT blades. Flight data records (FDR) for a specific aircraft, provided by a commercial aviation company, were used to obtain thermal and mechanical data for three different flight cycles. In order to create the 3D model needed for the FEM analysis, a HPT blade scrap was scanned, and its chemical composition and material properties were obtained. The data that was gathered was fed into the FEM model and different simulations were run, first with a simplified 3D rectangular block shape, in order to better establish the model, and then with the real 3D mesh obtained from the blade scrap. The overall expected behaviour in terms of displacement was observed, in particular at the trailing edge of the blade. Therefore such a model can be useful in the goal of predicting turbine blade life, given a set of FDR data.
Inorganic Chemistry, 2021
Nitrogen doping has been shown to greatly improve the stability of solid electrolyte (SE) materia... more Nitrogen doping has been shown to greatly improve the stability of solid electrolyte (SE) materials at the anode and cathode interfaces in all solid-state batteries (ASSBs) as widely demonstrated by the LiPON family of compositions. In an effort to expand the use of nitrogen in SEs, in this study, mixed oxy-sulfide nitride (MOSN) glasses were prepared by direct ammonolysis of the sodium oxy-sulfide phosphate Na4P2S7-xOx (NaPSO) glass series to understand the combined effects that oxygen and sulfur have on the incorporation of nitrogen. The short-range order (SRO) structures of the Na4P2S(7-x)-3/2yzOx-3/2y(1-z)Ny (NaPSON) glasses were investigated with Raman and infrared (IR) spectroscopies to understand the effect that nitrogen has in the glass structure. The N content of the glasses was quantified by elemental analysis and confirmed through weight change measurements. By combining this information, it was further possible to determine the anion exchange ratio, z, for the N substitution of O and S as a function of the base NaPSO glass chemistry, x. The composition-dependent glass transition temperature, Tg(x), measured with differential scanning calorimetry (DSC), was found to correlate well with the measured N/P ratio, y, in the NaPSON glasses.
Advanced energy materials, Jun 29, 2024
Chemistry of materials, May 29, 2024
Inorganic chemistry, May 6, 2024
The journal of physical chemistry. A/The journal of physical chemistry. A., Apr 25, 2024
Angewandte Chemie, Apr 16, 2024
Batteries & supercaps, Oct 13, 2022
The short-range order (SRO) structures of glasses in the Na4P2S 7-xOx, 0 ≤ x ≤ 7, series were inv... more The short-range order (SRO) structures of glasses in the Na4P2S 7-xOx, 0 ≤ x ≤ 7, series were investigated on samples prepared by planetary ball milling (PBM). Like other glasses prepared by PBM, the glassy nature of the prepared materials was confirmed by x-ray diffraction (XRD) showing that they were structurally amorphous and by differential scanning calorimetry (DSC) showing that each composition exhibited a reproducible glass transition temperature (Tg). The short-range order (SRO) structure of these glasses were determined using Raman, Fourier Transform Infrared (FT-IR), and 31 P Magic Angle Spinning NMR (MAS NMR) spectroscopies to investigate how oxygen and sulfur are bonded in the various SRO structural units that were found in these glasses. The three spectroscopic techniques gave further evidence that the resulting glasses were completely reacted from their polycrystalline starting materials Na2S, P2S5 and P2O5. It was found that significant disproportionation reactions occur in these compositions in which the original as batched and expected pyro-phosphate SRO units, P 1 = 2 Na/P, for x = 0 undergo a transformation to form ortho-phosphate (P 0 , 3 Na/P) and meta-phosphate (P 2 , 1 Na/P) SRO structures with increasing x such that there is a conservation of Na + charge, on average 2Na/P. In this nomenclature, the superscript describes the number of bridging sulfurs (BSs) and the number of Na per P plus one (arising from the P +5 valency) describing the number of non-bridging sulfurs (NBSs) on each of the SRO units. As seen in earlier work on other mixed oxy-sulfide (MOS) glass forming systems, the stronger Lewis base O = , compared to S = , is found to preferentially form bridging oxygen (BOs) in the form of P 2 SRO units by bonding to the stronger Lewis acid P +5 , compared to Na +. This leaves the weaker Lewis base S = to bond to the weaker Lewis acid, Na + in the form of non-bridging sulfurs (NBSs) on the charge compensation required P 0 groups. Using both charge balance and quantitative 31 P MAS NMR measurements, a complete composition map of all of the SRO structures present in these glasses has been created.
Batteries & Supercaps
Nature Communications
All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage.... more All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage. However, there are no commercialized ASSSBs yet, in part due to the lack of a low-cost, simple-to-fabricate solid electrolyte (SE) with electrochemical stability towards Na metal. In this work, we report a family of oxysulfide glass SEs (Na3PS4−xOx, where 0 < x ≤ 0.60) that not only exhibit the highest critical current density among all Na-ion conducting sulfide-based SEs, but also enable high-performance ambient-temperature sodium-sulfur batteries. By forming bridging oxygen units, the Na3PS4−xOx SEs undergo pressure-induced sintering at room temperature, resulting in a fully homogeneous glass structure with robust mechanical properties. Furthermore, the self-passivating solid electrolyte interphase at the Na|SE interface is critical for interface stabilization and reversible Na plating and stripping. The new structural and compositional design strategies presented here provide a ne...
ECS Meeting Abstracts, 2021
Solid-state batteries present many advantages over liquid electrolyte systems, enabling the use o... more Solid-state batteries present many advantages over liquid electrolyte systems, enabling the use of lithium metal anodes due to the non-flammable nature of the inorganic electrolyte. Glassy materials in particular are promising candidates as solid electrolytes due to their highly tunable properties, the absence of grain boundaries, and their ease of processability. The large compositional window of glassy materials allows for optimizing glass-forming ability and conductivity, while the lack of grain boundaries may be beneficial in preventing lithium dendrite formation. While lithium metaphosphate (LiPO3) has a low room temperature ionic conductivity (σ25°C = 1.6 ∙ 10-9 S/cm) that limits its use in solid-state batteries, oxides present similar processability and higher chemical and electrochemical stability than their higher conductivity sulfide analogues. LiPO3 was chosen for a preliminary investigation into the effects and challenges of decreasing electrolyte thickness due to its lo...
ACS Applied Materials & Interfaces, 2021
Glassy sulfide materials have been considered as promising candidates for solid-state electrolyte... more Glassy sulfide materials have been considered as promising candidates for solid-state electrolytes (SSEs) in lithium and sodium metal (LM and SM) batteries. While much of the current research on lithium glassy SSEs (GSSEs) has focused on the pure sulfide binary Li2S + P2S5 system, we have expanded these efforts by examining mixed-glass-former (MGF) compositions which have mixtures of glass formers, such as P and Si, which allow melt-quenching synthesis under ambient pressure and therefore the use of grain-boundary-free SSEs. We have doped these MGF compositions with oxygen to improve the chemical, electrochemical, and thermal properties of these glasses. In this work, we report on the short-range order (SRO), namely atomic-level, structures of Li2S + SiS2 + P2O5 MGF mixed oxy-sulfide glasses and, for the first time, study the critical current density (CCD) of these Si-doped oxy-sulfide GSSEs in LM symmetric cells. The samples were synthesized by planetary ball milling (PBM), and it was observed that a certain minimum milling time was necessary to achieve a final SRO structure. To address the short-circuiting lithium dendrite (LD) problems that were observed in these GSSEs, we demonstrate a simple and novel strategy for these Si-doped oxy-sulfide GSSEs to engineer the LM-GSSE interface by forming an in situ interlayer via heat treatment. Stable cycling to ∼1200 h at a capacity of 2 mAh·cm-2 per discharge/charge cycle under a current density of 1 mA·cm-2 is achieved. These results indicate that these MGF oxy-sulfide GSSEs combined with an optimized interfacial modification may find use in LM, and by extrapolation, SM, batteries.
All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage ... more All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage applications. To date, however, there are no commercialized ASSSBs due in part to the lack of a solid electrolyte (SE) that meets all of the requirements of low cost, facile fabrication, high Na+ conductivity, electrochemical stability, and is resistant to sodium metal dendrite penetration. In this work, we report a family of oxysulfide glass SEs (Na3PS4−xOx, where 0 < x ≤ 0.6) that combine the advantages of sulfides and oxides, we demonstrate stable electrochemical cycling of Na metal for hundreds of hours and the highest critical current density of 2.3 mA cm−2 among all Na-ion conducting sulfide-based SEs. These performance enhancements are found to be associated with the ability of the oxysulfide glass to undergo room temperature pressure induced amorphization that creates a fully homogeneous glass structure that has robust mechanics and substantial chemical and electrochemical sta...
Journal of Non-Crystalline Solids, 2021
During their operation, modern aircraft engine components are subjected to increasingly demanding... more During their operation, modern aircraft engine components are subjected to increasingly demanding operating conditions, especially the high pressure turbine (HPT) blades. Such conditions cause these parts to undergo different types of time-dependent degradation, one of which is creep. A model using the finite element method (FEM) was developed, in order to be able to predict the creep behaviour of HPT blades. Flight data records (FDR) for a specific aircraft, provided by a commercial aviation company, were used to obtain thermal and mechanical data for three different flight cycles. In order to create the 3D model needed for the FEM analysis, a HPT blade scrap was scanned, and its chemical composition and material properties were obtained. The data that was gathered was fed into the FEM model and different simulations were run, first with a simplified 3D rectangular block shape, in order to better establish the model, and then with the real 3D mesh obtained from the blade scrap. The overall expected behaviour in terms of displacement was observed, in particular at the trailing edge of the blade. Therefore such a model can be useful in the goal of predicting turbine blade life, given a set of FDR data.
Inorganic Chemistry, 2021
Nitrogen doping has been shown to greatly improve the stability of solid electrolyte (SE) materia... more Nitrogen doping has been shown to greatly improve the stability of solid electrolyte (SE) materials at the anode and cathode interfaces in all solid-state batteries (ASSBs) as widely demonstrated by the LiPON family of compositions. In an effort to expand the use of nitrogen in SEs, in this study, mixed oxy-sulfide nitride (MOSN) glasses were prepared by direct ammonolysis of the sodium oxy-sulfide phosphate Na4P2S7-xOx (NaPSO) glass series to understand the combined effects that oxygen and sulfur have on the incorporation of nitrogen. The short-range order (SRO) structures of the Na4P2S(7-x)-3/2yzOx-3/2y(1-z)Ny (NaPSON) glasses were investigated with Raman and infrared (IR) spectroscopies to understand the effect that nitrogen has in the glass structure. The N content of the glasses was quantified by elemental analysis and confirmed through weight change measurements. By combining this information, it was further possible to determine the anion exchange ratio, z, for the N substitution of O and S as a function of the base NaPSO glass chemistry, x. The composition-dependent glass transition temperature, Tg(x), measured with differential scanning calorimetry (DSC), was found to correlate well with the measured N/P ratio, y, in the NaPSON glasses.