Plastic deformation induced microstructure transition in nano-fibrous Al-Si eutectics
Not Available
36 MATERIALS SCIENCE↗
SEARCH · Engineering Papers
Results for “SI”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Materials Data on Si(NF3)2 by Materials Project
Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations
36 MATERIALS SCIENCE↗
Materials Data on Si(NF2)2 by Materials Project
N2SiF4 is Cyanogen Chloride-derived structured and crystallizes in the orthorhombic Immm space group. The structure is zero-dimensional and consists of twelve ammonia molecules and six silane, tetrafluoro- molecules.
36 MATERIALS SCIENCE↗
Design and performance of an additively manufactured high-Si transformer core
Not Available
36 MATERIALS SCIENCE↗
Examining Effects of Negative to Positive Capacity Ratio in Three-Electrode Lithium-Ion Cells with Layered Oxide Cathode and Si Anode
The negative to positive electrode capacity ratio (N:P) is crucial for lithium-ion cell design because it affects both energy density and long-term performance. Here, the effect of N:P ratio on electrochemical performance has been investigated for NMC 532 /Si cells containing a reference electrode. By monitoring individual electrode potentials, depths of lithiation/delithiation at the anode and cathode could be determined. The superior performance of the higher N:P cell, including greater reversibility, better capacity retention and lower impedance rise, can be attributed to smaller volume changes in the silicon particles during electrochemical cycling.
25 ENERGY STORAGE↗
Utilizing three-terminal, interdigitated back contact Si solar cells as a platform to study the durability of photoelectrodes for solar fuel production
Demonstration of a new three-terminal semiconductor photoabsorber architecture for photoelectrochemical fuel production that enables protection of the semiconductor in the dark.
14 SOLAR ENERGY↗
Materials Data on Hg3(SI)2 by Materials Project
Hg3S2I2 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. there are three inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded in a 4-coordinate geometry to two equivalent S2- and two equivalent I1- atoms. Both Hg–S bond lengths are 2.48 Å. Both Hg–I bond lengths are 3.18 Å. In the second Hg2+ site, Hg2+ is bonded in a 6-coordinate geometry to two equivalent S2- and four I1- atoms. Both Hg–S bond lengths are 2.45 Å. There are a spread of Hg–I bond distances ranging from 3.19–3.78 Å. In the third Hg2+ site, Hg2+ is bonded in a 5-coordinate geometry to two equivalent S2- and three I1- atoms. Both Hg–S bond lengths are 2.47 Å. There are a spread of Hg–I bond distances ranging from 3.08–3.69 Å. S2- is bonded in a distorted trigonal non-coplanar geometry to three Hg2+ atoms. There are three inequivalent I1- sites. In the first I1- site, I1- is bonded in a 3-coordinate geometry to four Hg2+ atoms. In the second I1- site, I1- is bonded in a 2-coordinate geometry to four equivalent Hg2+ atoms. In the third I1- site, I1- is bonded in a 6-coordinate geometry to six Hg2+ atoms.
36 MATERIALS SCIENCE↗
Materials Data on Si by Materials Project
Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations
36 MATERIALS SCIENCE↗
Reliability of TOPCon Solar Cells: Understanding Degradation and Recovery of Poly-Si/SiOx Passivating Contacts
A presentation recommending that TOPCon modules and/or cells should have surface passive degradation tests performed, and should be treated with surface passivation recovery.
14 SOLAR ENERGY↗
Understanding Hydrogen Passivation Mechanism in Poly-Si Passivating Contacts: Insights from Effusion Studies
Silicon PV is the dominant PV technology, and captures >95% world market share, supporting -100 GW/year. Diffused and passivated pn junctions along with other rear side passivation technologies are the mainstream technologies and will continue to remain so in the coming decades. Passivated contacts, using tunnel oxide passivation stacks at the rear side, will gain market share from about 10% in 2022 up to 58% within the next 10 years. Most mature approaches use passivating layers of hydrogenated Al2O3 and SiNx. LPCVD SiNx provides less hydrogen for passivation compared to PECVD SiNx but can retain the hydrogen up to higher temperatures which is beneficial for firing. Although SiNx provides large amount of hydrogen, this doesn't necessarily translate to good passivation. AlOx:H contributes to retaining H at higher temperatures. Water molecules are also detected during H-effusion and may play a role in passivation of the oxide/wafer interface.
effusion study↗
Pitch Carbon-coated Ultrasmall Si Nanoparticle Lithium-ion Battery Anodes Exhibiting Reduced Reactivity with Carbonate-based Electrolyte
Silicon anodes for lithium-ion batteries (LIBs) have the potential for higher energy density compared to conventionally used graphite-based LIB anodes. However, silicon anodes exhibit poor cycle and calendar lifetimes due to mechanical instabilities and high chemical and electrochemical reactivity with the carbonate-based electrolytes that are typically used in LIBs. In this work, we synthesize a pitch carbon-coated silicon nanoparticle composite active material for LIB anodes that exhibits reduced chemical reactivity with carbonate-based electrolytes compared to an uncoated silicon anode. Silicon primary particle sizes less than 10 nm diameter minimize micro-scale mechanical degradation of the anode composite, while conformal coatings of pitch carbon minimize the parasitic reactions between the silicon and the electrolyte. When matched with a high voltage NMC622 (LiNi 0.6 Mn 0.2 Co 0.2 O 2 ) cathode, the pitch carbon-coated silicon anode retains approximately 75% of its initial capacity at the end of 1000 cycles. Increasing the areal loading of the pitch carbon-coated silicon anodes to realize energy density improvements over graphite anodes results in severe mechanical degradation on the electrode level, highlighting a remaining challenge to be addressed in future work.
25 ENERGY STORAGE↗
Hydrosilane σ‐Adduct Intermediates in an Adaptive Zinc‐Catalyzed Cross‐dehydrocoupling of Si−H and O−H Bonds
Abstract Three‐coordinate Ph BOX ZnR ( Ph BOX =phenyl‐(4,4‐dimethyl‐oxazolinato; R=Me: 2 a , Et: 2 b ) catalyzes the dehydrocoupling of primary or secondary silanes and alcohols to give silyl ethers and hydrogen, with high turnover numbers (TON; up to 10 7 ) under solvent‐free conditions. Primary and secondary silanes react with small, medium, and large alcohols to give various degrees of substitution, from mono‐ to tri‐alkoxylation, whereas tri‐substituted silanes do not react with MeOH under these conditions. The effect of coordinative unsaturation on the behavior of the Zn catalyst is revealed through a dramatic variation of both rate law and experimental rate constants, which depend on the concentrations of both the alcohol and hydrosilane reactants. That is, the catalyst adapts its mechanism to access the most facile and efficient conversion. In particular, either alcohol or hydrosilane binds to the open coordination site on the Ph BOX ZnOR catalyst to form a Ph BOX ZnOR(HOR) complex under one set of conditions or an unprecedented σ‐adduct Ph BOX ZnOR(H−SiR′ 3 ) under other conditions. Saturation kinetics provide evidence for the latter species, in support of the hypothesis that σ‐bond metathesis reactions involving four‐centered electrocyclic 2σ–2σ transition states are preceded by σ‐adducts.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Performance and durability of electrically conductive tape for shingled Si heterojunction technology cells
We report electrically conductive tape (ECT) was characterized and used to assemble shingled cell strings at low temperature to achieve high reliability Pb- and Ag-free interconnections. The volume resistivity for two considered ECTs are 0.13 ± 0.06 mΩ·cm and 0.47 ± 0.20 mΩ·cm and specific contact resistances, 6.85± 2.00 mΩ·cm 2 and 6.30 ± 0.37 mΩ·cm 2 using the emerging IEC 62788-8-1 Technical Specification for assessment of electrically conductive adhesives (ECA). Durability and performance of the technology in glass–glass mini modules were evaluated with temperature cycling, damp heat testing, and combined-accelerated stress testing (CAST). Through temperature cycling (-40°C to 85°C) applying five times the mini module short-circuit current in forward bias and in the multi climate CAST protocol, there was negligible degradation of fill factor after replacing connectors at the modules' cable leads; however, CAST resulted in short circuit current loss attributed to degradation in light collection by the cells, not the ECT. The IEC 61215-2 85°C, 85% relative humidity damp heat testing showed susceptibility of the HJT cells to effects of humidity in the electroluminescence intensity around the module perimeter that degraded power performance by 4% (relative). Contrasting the IEC 61215-2 qualification testing-based damp heat testing with CAST, factors such as the optical stress of CAST may precipitate the degradation of the modules whereas the humidity levels and duration of IEC 61215-2 damp heat testing may lead to excessive levels of humidity diffused into the modules, potentially resulting in degradation that is unrepresentative of the field.
14 SOLAR ENERGY↗