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At least 217 records · Page 12

The Dominant Effect of Electrolyte Concentration on Rechargeability of γ -MnO 2 Cathodes in Alkaline Batteries

Achieving high cycle life rechargeableγ-MnO 2 cathodes in alkaline batteries face many challenges. Chief among these is the inability of theγ-MnO 2 polymorph to retain its structural integrity when cycled to high utilization of its theoretical capacity ∼300 mAh g −1 . In this paper, we investigate the root cause of failure of MnO 2 cathodes under deep cycling in the one-electron discharge range and establish a strong link between capacity fade and the amount of birnessite formed. We uncover the underlying cause of failure by cycling industrial scaleγ-MnO 2 cathodes at various levels of theoretical capacity utilization (100%, 50%, and 30%) and in different KOH concentrations (37, 25, and 10 wt%). To determine materials evolution the cycled cathodes were dissected, characterized and analyzed using SEM, XRD, FIB/SEM, EIS, and XPS. Based on our findings, we propose that one major cause of failure of MnO 2 cathodes stems from the solubility of Mn +3 formed during discharge which effectively results in destruction of theγ-MnO 2 phase and amorphization of the cathode. The results show that the bulk of theγ-MnO 2 phase is preserved only in ∼10 wt% KOH, which indicates the attractive range of KOH concentration for cycling of rechargeableγ-MnO 2 cathodes.

Electrochemistry↗

Stability of a Ni/NiF 2 Reference Electrode with a Metallic Membrane for Use in Molten Fluoride Salts

In this study, an experimental high-temperature fluoride salt reference electrode (RE) developed by HiFunda LLC was tested in molten FLiNaK at 550 °C. The high-temperature reference electrode (HTRE), based on the Ni/NiF 2 redox couple, was tested over a period of 13 d for short-term stability, long-term stability, and electrochemical analysis capabilities. The HTRE was tested using open circuit potentiometry (OCP), cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS). The HTRE reference potential was measured against changes in salt composition by increasing FeF 2 concentrations in the melt across six additions from 0 to 0.1 mol% FeF 2 . The long-term stability of the electrode was then tested over ten days at a constant composition of 0.1 mol% FeF 2 . OCP, SWV, and CV were used to calculate an average potential drift between 7–10 mV per day. Using CV and SWV, the number of electrons transferred for iron reduction and the diffusion coefficient of Fe 2+ were measured.

Electrochemistry↗

Plasticizer-Free Gradient-Crosslinked Polyurethane Electrolyte for Room-Temperature Solid-State Lithium Batteries

Polymer-based solid-state electrolytes are promising for next-generation lithium metal batteries, yet their limited ionic conductivity and mechanical stability at ambient conditions remain key challenges. Herein, we report a novel gradient crosslinked polymer electrolyte (PU/PUA/PU) synthesized via a sequential in situ UV-curing process that integrates a mechanically robust polyurethane acrylate (PUA) core with soft linear polyurethane (PU) interfaces. This all-solid membrane operates without any liquid plasticizer and the interfacial PU layers ensure low interfacial resistance and intimate electrode contact, while the PUA core provides enhanced dimensional stability and dendrite suppression. As a result, the gradient electrolyte delivers an impressive ∼2.6 × 10 −4 S cm −1 ionic conductivity at 25 °C (two orders of magnitude higher than conventional PEO) and remains electrochemically stable >5 V (vs Li + /Li). Structural analysis confirms the formation of a well-defined crosslinked network with suppressed crystallinity and expanded interchain spacing. Electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) further validate these properties. When applied in a Li||NMC811 cell, the PU/PUA/PU electrolyte delivers stable cycling with high capacity at both 60 °C and 25 °C, demonstrating its potential for room-temperature solid-state battery applications without reliance on plasticizers or heating. In conclusion, this gradient design offers a practical path toward ambient-condition operation of solid-state lithium batteries, providing a paradigm for overcoming the traditional trade-off between ionic conductivity and mechanical robustness.

25 ENERGY STORAGE↗

Investigating the Influence of Ni, ZrO 2 , and Y 2 O 3 from SOFC Anodes on Siloxane Deposition

Siloxanes, as a type of impurity in biogas, can poison the Ni-YSZ anode of SOFCs. However, the influence of individual components of the anode, such as Ni, ZrO 2 , and Y 2 O 3 , on the siloxane deposition process has not been investigated extensively. In this study, Ni, ZrO 2 , and Y 2 O 3 pellets were exposed to H 2 + N 2 + H 2 O + D4 (octamethylcyclotetrasiloxane, 2.5 ppmv) and H 2 + N 2 + D4 (2.5 ppmv siloxane) gas mixtures at 750 °C to investigate their affinity and tolerance for siloxane degradation. Surface morphology analysis and electrochemical analysis including electrochemical impedance spectroscopy (EIS), related distribution of relaxation times (DRT) analysis and equivalent circuit modeling with complex nonlinear least square (CNLS) fitting were conducted. Here, a microstructure parameter—tortuosity factor to porosity ratio $\tau /\varepsilon $ calculated by diffusion polarization resistance was utilized for siloxane deposition evaluation. After comparing pellets surface morphology changes before and after experiments and $\tau /\varepsilon $ change following the contamination, Ni is considered as a major factor in siloxane deposition reactions in Ni-YSZ anode.

25 ENERGY STORAGE↗

Optimization of Lithium Content and Sintering Additives in Tape Cast Lithium Garnet Electrolyte Sheets

The lithium garnet (LLZO) remains one of the most promising electrolyte materials for producing solid state batteries. Tape casting is one method for producing the thin ceramic electrolyte layer required for a high-performance solid state battery. Processing of LLZO is complicated by several factors including lithium volatilization, abnormal grain growth and phase instability. Many of these issues are exacerbated in tape cast sheets by the sheets' higher surface area to volume ratio, when compared to pellet processing methods. Here, we report on an environmentally friendly aqueous tape casting process for LLZO using methylcellulose as a binder and compare final sheet properties to other, solvent-based, options. Solids loading, binder content, dispersant composition, and wetting agent type are varied to improve ease of casting and enhance properties of the as-cast tape. Lithium content in sintered LLZO sheets is controlled by the inclusion of excess Li 2 CO 3 as lithium source in the ceramic tape itself and by a novel method of producing a lithium-saturated furnace atmosphere. Sintering time and temperature are optimized, and rapid thermal processing is investigated as a method of reducing lithium loss. Al 2 O 3 and MgO are examined for use as sintering additives. Characterization of LLZO sheets is performed with XRD, EIS and SEM. Li 2 CO 3 and sintering additive levels are optimized for ionic conductivity and density. The optimization effort improved the conductivity and density of 100µm thick sintered sheets to greater than 3x10 -4 S/cm conductivity and 90% density.

36 MATERIALS SCIENCE↗

Mapathons versus automated feature extraction: a comparative analysis for strengthening immunization microplanning

Background: Social instability and logistical factors like the displacement of vulnerable populations, the difficulty of accessing these populations, and the lack of geographic information for hard-to-reach areas continue to serve as barriers to global essential immunizations (EI). Microplanning, a population-based, healthcare intervention planning method has begun to leverage geographic information system (GIS) technology and geospatial methods to improve the remote identification and mapping of vulnerable populations to ensure inclusion in outreach and immunization services, when feasible. We compare two methods of accomplishing a remote inventory of building locations to assess their accuracy and similarity to currently employed microplan line-lists in the study area. Methods: The outputs of a crowd-sourced digitization effort, or mapathon, were compared to those of a machine-learning algorithm for digitization, referred to as automatic feature extraction (AFE). The following accuracy assessments were employed to determine the performance of each feature generation method: (1) an agreement analysis of the two methods assessed the occurrence of matches across the two outputs, where agreements were labeled as “befriended” and disagreements as “lonely”; (2) true and false positive percentages of each method were calculated in comparison to satellite imagery; (3) counts of features generated from both the mapathon and AFE were statistically compared to the number of features listed in the microplan line-list for the study area; and (4) population estimates for both feature generation method were determined for every structure identified assuming a total of three households per compound, with each household averaging two adults and 5 children. Results: The mapathon and AFE outputs detected 92,713 and 53,150 features, respectively. A higher proportion (30%) of AFE features were befriended compared with befriended mapathon points (28%). The AFE had a higher true positive rate (90.5%) of identifying structures than the mapathon (84.5%). The difference in the average number of features identified per area between the microplan and mapathon points was larger (t = 3.56) than the microplan and AFE (t = -2.09) (alpha = 0.05). Conclusions: Our findings indicate AFE outputs had higher agreement (i.e., befriended), slightly higher likelihood of correctly identifying a structure, and were more similar to the local microplan line-lists than the mapathon outputs. These findings suggest AFE may be more accurate for identifying structures in high-resolution satellite imagery than mapathons. However, they both had their advantages and the ideal method would utilize both methods in tandem.

59 BASIC BIOLOGICAL SCIENCES↗

Magnon gap tuning in lithium-doped MnTe

Data in this DOI includes: 1) Powder Diffraction at HFIR POWDER (HB-2A) of pure MnTe and 5%-lithium doped MnTe at various temperatures ranging from T = 4 - 360 K for pure MnTe and T = 4 - 290 K for 5% lithium doped MnTe. 2) Inelastic neutron scattering at ARCS of pure MnTe and 5% lithium doped MnTe at T = 10 K measured with incident energy Ei = 30 meV and 150 meV, and corresponding background files (i.e. empty can measurements)

diffraction↗

Observation of spin‑wave altermagnetic splitting in MnF2

-Contents of the Data Repository: - Polarized neutron diffraction data acquired in the (HK0) scattering plane. - Inelastic neutron scattering (INS) data from both unpolarized and polarized measurements with an incident neutron energy of Ei =9 meV.- - Reduced multidimensional single-crystal datasets (MDE) and corresponding S(Q,ω) slices used to generate all figures presented in the manuscript. - Julia source code and supporting input files used for spin-wave calculations, model fitting, and simulation of neutron scattering intensity maps.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Time-of-flight inelastic neutron scattering data of the quantum spin-Peierls chain CuGeO3

Inelastic neutron scattering data of co-aligned CuGeO3 single crystals (5.21 g). The data were collected at SEQUOIA time-of-flight spectrometer. The samples were mounted with the (0KL) plane horizontal. Co-alignment was achieved with overall mosaicity of 1 degree. The data were collected at 5 K, 20 K, 50 K, 100 K, and 150 K with incident neutron energies Ei = 24 and 60 meV and the standard high-resolution chopper condition.

36 MATERIALS SCIENCE↗

Materials Data on LiCoPO4F by Materials Project

LiCoPO4F crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- and one F1- atom to form distorted LiO4F trigonal bipyramids that share corners with two CoO4F2 octahedra, corners with four PO4 tetrahedra, a cornercorner with one LiO3F2 trigonal bipyramid, and edges with two CoO4F2 octahedra. The corner-sharing octahedra tilt angles range from 63–64°. There are a spread of Li–O bond distances ranging from 1.98–2.31 Å. The Li–F bond length is 2.00 Å. In the second Li1+ site, Li1+ is bonded in a 5-coordinate geometry to four O2- and one F1- atom. There are a spread of Li–O bond distances ranging from 1.88–2.52 Å. The Li–F bond length is 2.37 Å. In the third Li1+ site, Li1+ is bonded to three O2- and two F1- atoms to form distorted LiO3F2 trigonal bipyramids that share corners with two CoO4F2 octahedra, corners with three PO4 tetrahedra, a cornercorner with one LiO4F trigonal bipyramid, and edges with two CoO4F2 octahedra. The corner-sharing octahedra tilt angles range from 63–68°. There are a spread of Li–O bond distances ranging from 1.89–2.06 Å. There are one shorter (2.04 Å) and one longer (2.34 Å) Li–F bond lengths. In the fourth Li1+ site, Li1+ is bonded to four O2- and one F1- atom to form LiO4F trigonal bipyramids that share corners with two CoO4F2 octahedra, corners with four PO4 tetrahedra, and edges with two CoO4F2 octahedra. The corner-sharing octahedra tilt angles range from 64–65°. There are a spread of Li–O bond distances ranging from 1.96–2.22 Å. The Li–F bond length is 2.07 Å. In the fifth Li1+ site, Li1+ is bonded in a 5-coordinate geometry to four O2- and one F1- atom. There are a spread of Li–O bond distances ranging from 1.89–2.37 Å. The Li–F bond length is 2.49 Å. In the sixth Li1+ site, Li1+ is bonded in a 5-coordinate geometry to four O2- and one F1- atom. There are a spread of Li–O bond distances ranging from 1.96–2.33 Å. The Li–F bond length is 2.51 Å. In the seventh Li1+ site, Li1+ is bonded to four O2- and one F1- atom to form LiO4F trigonal bipyramids that share corners with two CoO4F2 octahedra, corners with four PO4 tetrahedra, and edges with two CoO4F2 octahedra. The corner-sharing octahedra tilt angles range from 60–62°. There are a spread of Li–O bond distances ranging from 1.95–2.19 Å. The Li–F bond length is 2.00 Å. In the eighth Li1+ site, Li1+ is bonded in a 4-coordinate geometry to three O2- and two F1- atoms. There are a spread of Li–O bond distances ranging from 1.98–2.05 Å. There are one shorter (1.91 Å) and one longer (2.49 Å) Li–F bond lengths. There are eight inequivalent Co3+ sites. In the first Co3+ site, Co3+ is bonded to four O2- and two F1- atoms to form CoO4F2 octahedra that share corners with four PO4 tetrahedra, edges with two equivalent CoO4F2 octahedra, and edges with two LiO4F trigonal bipyramids. There are a spread of Co–O bond distances ranging from 1.90–2.09 Å. There are one shorter (1.98 Å) and one longer (2.02 Å) Co–F bond lengths. In the second Co3+ site, Co3+ is bonded to four O2- and two F1- atoms to form CoO4F2 octahedra that share corners with four PO4 tetrahedra, edges with two equivalent CoO4F2 octahedra, and edges with two LiO4F trigonal bipyramids. There are a spread of Co–O bond distances ranging from 1.89–2.16 Å. There are one shorter (1.99 Å) and one longer (2.06 Å) Co–F bond lengths. In the third Co3+ site, Co3+ is bonded to four O2- and two F1- atoms to form CoO4F2 octahedra that share corners with four PO4 tetrahedra, a cornercorner with one LiO4F trigonal bipyramid, and edges with two equivalent CoO4F2 octahedra. There are a spread of Co–O bond distances ranging from 1.86–2.12 Å. There are one shorter (2.01 Å) and one longer (2.16 Å) Co–F bond lengths. In the fourth Co3+ site, Co3+ is bonded to four O2- and two F1- atoms to form CoO4F2 octahedra that share corners with four PO4 tetrahedra, a cornercorner with one LiO4F trigonal bipyramid, and edges with two equivalent CoO4F2 octahedra. There are a spread of Co–O bond distances ranging from 1.89–2.10 Å. There are one shorter (1.95 Å) and one longer (2.05 Å) Co–F bond lengths. In the fifth Co3+ site, Co3+ is bonded to four O2- and two F1- atoms to form CoO4F2 octahedra that share corners with four PO4 tetrahedra, a cornercorner with one LiO3F2 trigonal bipyramid, edges with two equivalent CoO4F2 octahedra, and an edgeedge with one LiO4F trigonal bipyramid. There are a spread of Co–O bond distances ranging from 1.83–2.23 Å. There are one shorter (1.99 Å) and one longer (2.12 Å) Co–F bond lengths. In the sixth Co3+ site, Co3+ is bonded to four O2- and two F1- atoms to form CoO4F2 octahedra that share corners with four PO4 tetrahedra, a cornercorner with one LiO3F2 trigonal bipyramid, edges with two equivalent CoO4F2 octahedra, and an edgeedge with one LiO4F trigonal bipyramid. There are a spread of Co–O bond distances ranging from 1.88–2.14 Å. There is one shorter (1.95 Å) and one longer (2.03 Å) Co–F bond length. In the seventh Co3+ site, Co3+ is bonded to four O2- and two F1- atoms to form CoO4F2 octahedra that share corners with four PO4 tetrahedra, corners with two LiO4F trigonal bipyramids, edges with two equivalent CoO4F2 octahedra, and an edgeedge with one LiO3F2 trigonal bipyramid. There are a spread of Co–O bond distances ranging from 1.89–2.17 Å. There are one shorter (2.01 Å) and one longer (2.02 Å) Co–F bond lengths. In the eighth Co3+ site, Co3+ is bonded to four O2- and two F1- atoms to form CoO4F2 octahedra that share corners with four PO4 tetrahedra, corners with two LiO4F trigonal bipyramids, edges with two equivalent CoO4F2 octahedra, and an edgeedge with one LiO3F2 trigonal bipyramid. There are a spread of Co–O bond distances ranging from 1.84–2.07 Å. There are one shorter (2.06 Å) and one longer (2.09 Å) Co–F bond lengths. There are eight inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CoO4F2 octahedra and a cornercorner with one LiO4F trigonal bipyramid. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of P–O bond distances ranging from 1.48–1.61 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CoO4F2 octahedra and corners with two equivalent LiO4F trigonal bipyramids. The corner-sharing octahedra tilt angles range from 49–53°. There are a spread of P–O bond distances ranging from 1.49–1.58 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CoO4F2 octahedra and a cornercorner with one LiO3F2 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of P–O bond distances ranging from 1.49–1.58 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CoO4F2 octahedra and corners with two LiO4F trigonal bipyramids. The corner-sharing octahedra tilt angles range from 54–57°. There are a spread of P–O bond distances ranging from 1.51–1.58 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CoO4F2 octahedra and corners with three LiO3F2 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of P–O bond distances ranging from 1.52–1.57 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CoO4F2 octahedra and corners with two equivalent LiO4F trigonal bipyramids. The corner-sharing octahedra tilt angles range from 48–57°. There are a spread of P–O bond distances ranging from 1.49–1.59 Å. In the seventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CoO4F2 octahedra and corners with two equivalent LiO4F trigonal bipyramids. The corner-sharing octahedra tilt angles range from 49–56°. There are a spread of P–O bond distances ranging from 1.51–1.58 Å. In the eighth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CoO4F2 octahedra and corners with two LiO4F trigonal bipyramids. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of P–O bond distances ranging from 1.51–1.58 Å. There are thirty-two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Li1+, two Co3+, and one P5+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Co3+ and one P5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Li1+, one Co3+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Co3+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Co3+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Co3+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Li1+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to one Li1+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Co3+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Co3+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Li1+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Co3+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Co3+, and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Co3+, and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Co3+ and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Li1+, two Co3+, and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Co3+, and one P5+ atom. In the nineteenth O2- site, O2- is bonded in a bent 120 degrees geometry to one Co3+ and one P5+ atom. In the twentieth O2- site, O2- is bonded in a 3-coordinate geometry to two Co3+ and one P5+ atom. In the twenty-first O2- site, O2- is bonded in a trigonal planar geometry to two Li1+ and one P5+ atom. In the twenty-second O2- site, O2- is bonded in a distorted tetrahedral geometry to two Li1+, one Co3+, and one P5+ atom. In the twenty-third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Co3+, and one P5+ atom. In the twenty-fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Li1+ and one P5+ atom. In the twenty-fifth O2- site, O2- is bonded in a distorted T-shaped geometry to two Li1+ and one P5+ atom. In the twenty-sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+, one Co3+, and one P5+ atom. In the twenty-seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Co3+, and one P5+ atom. In the twenty-eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Li1+ and one P5+ atom. In the twenty-ninth O2- site, O2- is bonded in a 3-coordinate geometry to two Co3+ and one P5+ atom. In the thirtieth O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+, one Co3+, and one P5+ atom. In the thirty-first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Co3+, and one P5+ atom. In the thirty-second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Li1+, two Co3+, and one P5+ atom. There are ei

36 MATERIALS SCIENCE↗

Impact of simultaneous activities on frequency fluctuations — comprehensive analyses based on the real measurement data from FNET/GridEye

Simultaneous human activities such as the Super Bowl game would cause certain impacts on frequency fluctuations in power systems. With the help of FNET/GridEye measurements, this work aims to give comprehensive analyses on the frequency fluctuations during Super Bowl LIV held on Feb. 2, 2020, so as to better understand several phenomena caused by simultaneous activities and help system operation and control. First, recent developments of FNET/GridEye are introduced briefly. Second, the frequency fluctuations of Eastern Interconnection (EI), western electricity coordinating council (WECC), and electric reliability council of Texas (ERCOT) power systems during Super Bowl LIV are analyzed. Third, frequency fluctuations of Super Bowl Sunday and ordinary Sundays in 2020 are compared. Finally, the differences of frequency fluctuations among different years during the Super Bowl and their change trend are also given. Furthermore, several possible explanations including the simultaneity of electricity consumption at the beginning of commercial breaks and the halftime show, the increasing usage of the Internet, and the increasing size of TV screens are illustrated in detail in this work.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Impedance and wakefield studies of the EIC RCS 591 MHz five-cell cavity

The Electron-Ion Collider (EIC) is a next-generation accelerator complex designed to enable high-luminosity collisions between highly polarized electrons and light ions (e.g., He-3). A central component of its Electron Injection System (EIS) is the Rapid Cycling Synchrotron (RCS), which accelerates a single 28 nC electron bunch from 750 MeV to 5, 10, or 18 GeV using an array of 591 MHz five-cell superconducting RF (SRF) cavities—eight at the current design stage. To ensure stable acceleration of high-charge bunches, we conducted detailed impedance and wakefield studies of the SRF cavity structure using both frequency- and time-domain methods. Wakefield solvers (ECHO3D, ECHO1D, CST), eigenmode analysis, and multi-particle tracking with ELEGANT were employed to evaluate longitudinal and transverse impedance effects and to determine instability thresholds. These studies provide critical input for the cavity design and operating parameters required to preserve beam quality and stability in the RCS.

Accelerator Physics↗

Cloud-Control of Legacy Building Automation System: A case study

As Internet of Things devices and cloud-based platforms become more mature, Energy Management and Information Systems (EMIS) are increasingly gaining momentum in the building industry. In large commercial buildings, Fault-Detection and Diagnostic (FDD) and energy information systems (EIS) are now established technologies with tens of providers and thousands of deployment sites across North America. The new frontier for the EMIS technology is now represented by control systems that use advanced system optimization (ASO) methods to improve the operations of the HVAC system. Given the complexity of the integration of such systems with the existing building automation systems (BAS) and the higher risk involved with direct control of the HVAC, these systems are still emerging in the market. This paper presents the results of a project in which a start-up company partnered with a research institution to develop a cloud-based software EMIS solution and deployed it in a university campus in California. The software system included advanced sensing, data acquisition, storage and advanced control and analytics applications developed on top of the native BAS. The new platform controls ten buildings on the campus and the FDD and the ASO applications deployed on this platform were able to generate energy savings of up to 35% and 25% in certain buildings for each functionality respectively. Where the platform did not save energy, it improved building service (air quality). Lessons learned include the importance of collaborating with and training the building operators and evaluating whether the legacy system can work reliably with the new technology.

Prakash, Anand Krishnan↗

Research three-dimensional hierarchical graphite architectures for anodes for fast charging

With current lithium ion batteries optimized for performance under relatively low charge rate conditions, implementation of XFC has been hindered by drawbacks including Li plating, kinetic polarization, and heat dissipation. This project will utilize model-informed design of 3-D hierarchical electrodes to tune key XFCrelated variables like 1) bulk porosity/tortuosity 2) vertical pore diameter, spacing, and lattice 3) crystallographic orientation of graphite particles relative to exposed surfaces 4) interfacial chemistry of the graphite surfaces through "artificial sEr' formation using ALD 5) current collector surface roughness (aspect ratio, roughness factor, etc.). A key aspect of implementing novel electrodes is characterizing them in relevant settings. For this project, ultimately led out of University of Michigan by Neil Dasgupta, that includes both coin cell and 2+ Ah pouch cell testing, as well as comparison testing against baselines. Sandia National Labs will be conducting detailed cell characterization on iterative versions/improvements of the model-based hierarchical electrodes, as well as COTS cells for baseline comparisons. Key metrics include performance under fast charge conditions, as well as the absence or degree of lithium plating. Sandia will use their unique high precision cycling and rapid EIS capabilities to accurately characterize performance and any lithium plating during 6C charging and beyond, coupling electrochemical observations with cell teardown. Sandia will also design custom fixturing to cool cells during rapid charge, to decouple any kinetic effects brought about by cell heating and allow comparisons between different cells and charge rates. Using these techniques, Sandia will assess HOH electrodes from the University of Michigan, as well as aiding in iterative model and electrode design.

25 ENERGY STORAGE↗

Seismic Isolation of Major Advanced Reactor Systems for Economic Improvement and Safety Assurance

Advanced reactor concepts currently under development in the United States [e.g., the High-Temperature Gas Reactor (HTGR) of X-Energy and the Molten Chloride Fast Reactor (MCFR) of TerraPower] are striving to improve the economics of nuclear power primarily by using passively and ‘walk-away’ safe technologies in the reactor. The recently published report, ‘Future of Nuclear Energy in a Carbon-Constrained World’ by the Massachusetts Institute of Technology Energy Institute (MIT EI) has shown that a significant contributor to the capital cost of NPPs is the ‘civil works’ i.e., the construction of the balance of plant (BoP: all SSCs except those involved in power generation, e.g., reactor vessel) such as the buildings, containment dome, foundation, etc., which amount to almost half of the overnight capital cost. The report suggests that using advanced construction technologies such as seismic isolation and high-performance concrete to significantly reduce the capital costs of advanced reactors. This report demonstrates the application of two cost-cutting solutions on advanced reactor designs that are currently under development. These solutions include, (1) seismic base isolation, and (2) risk- and cost-based seismic design optimization including seismic isolation of individual components.

42 ENGINEERING↗

Data call questions related to potential NEPA/Data gaps

Based on review of the related NEPA documents, and consideration of the potential gaps in NEPA coverage, a number of questions have been generated. These questions are generally higher level (less detailed) questions that should help to establish the applicability of analyses in existing NEPA documents and the ability of these documents to provide NEPA coverage for the Proposed Action. These questions do not request detailed information about SRS facilities/activities and the Proposed Action like typically would be requested when performing impacts analyses for an EIS. We do not believe detail information is needed; if it is needed, it may be an indication that an SA is not the appropriate level of NEPA documentation for the Proposed Action.

54 ENVIRONMENTAL SCIENCES↗

Developing Accelerated Test Protocols and Tuning Microstructures of the Common Materials to Improve Robustness, Reliability, and Endurance of SOFC Cells

This work is built on our prior work where we found that phase transformation in praseodymium nickelates, e.g. Pr 2 NiO 4 (PNO) and (Pr 1-x Nd x ) 2 NiO 4 (PNNO), can be electrochemically driven, and is substantially faster when compared to thermal annealing studies. The first task aims at an attempt to further accelerate the phase transformation in the oxygen electrode by alternating the current input in the cells, which lead to the development of accelerated test protocols (ATPs). ATPs showed up to 60x faster phase transformation and up to 10x faster performance degradation in (Pr 0.50 Nd 0.50 ) 2 NiO 4 electrodes, when compared to long-term operation under constant current density. Furthermore, the phase stable Nd 2 NiO 4 and (La 0.6 Sr 0.4 )(Co 0.8 Fe 0.2 )O 3 (LSCF6482) electrodes were tested in full cells under ATPs, and showed up to 10x faster performance degradation within 1,100 hours in a comparison with long-term thermal annealing studies and electrochemical operation under constant current density. The second task aims at the quantification of the contributions of cell components to the total impedance of a solid oxide fuel cell (SOFC) using electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRT). Specifically, the role of gas composition at both anode and cathode was systematically studied, aiming at deconvoluting, identifying and quantifying the contributions of different electrode processes. This was achieved by first tuning the partial pressure of H 2 at the anode and subsequently varying the partial pressure of O 2 at the cathode. The results suggest that, while DRT offers a viable way of deconvoluting different times distributions, additional attention is needed before assigning a peak to a specific electrode process due to the significant overlap of the contributions from the cathode and the anode. Density function theory studies show that both Pr-vacancies and O-defects play a key role on the activity and stability for nickelates towards oxygen reduction reaction. The resident O-interstitials and oxygen ions in the PrO layer form peroxide (O 2 2- ) nearby Pr vacancies. The O 2 2- limits oxygen-ion transport due to the required additional energy to break its O-O bond. We further calculated the formation and segregation energies for different Ln ions (La, Pr, Nd, Pm, Sm, Gd, Tb, Dy, and Ho) in PNO and CeO 2 (111) surfaces. In addition to Nd, Pm and La are suggested as potential dopants in PNO to enhance it stability without decomposition due to their more negative formation energies, lower diffusion energies, and positive separation energies.

01 COAL, LIGNITE, AND PEAT↗