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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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Iron nanoparticles implanted metal-organic-frameworks based Fe–N–C catalysts for high-performance oxygen reduction reaction
Abstract not provided
Bio-inspired redox mediated electrolyte for high performance flexible supercapacitor applications over broad temperature domain
For practical supercapacitors, recent advances in electrolytes have diminished long-standing problems such chemical stability, low ionic conductivity and limited electrochemical performance. Herewith, we communicate a facile method to produce anhydrous redox-active Bio-inspired electrolytes for flexible supercapacitors with application over a broad temperature range. The glycerol (Gly) gel electrolyte consists of various fractions of potassium hydroxide (KOH) and redox active unit, i.e., ammonium molybdate, (NH 4 ) 2 MoO 4 (abbreviated as Mo), in the anhydrous state. The doped glycerol matrix acts as a framework that provides a stable gel electrolyte, forming hierarchical pathway for ion diffusion. The developed gel network with Gly-KOH-MoX (X = 3, 5, 10, and 15%, w/w) provides an effective route to carry the ions onto the pores of the electrodes. The supercapacitor with Gly-KOH5-Mo10 gel provides a specific capacitance of 328 F g –1 , and the same device achieved an energy density of 45.6 Wh kg –1 at a power density of 497 W kg –1 . In addition, the supercapacitor maintained extraordinary cyclic robustness and wide temperature tolerance. Thus, the low cost and environmentally benign, cyclic durability of Gly-KOH-Mo makes these gel electrolytes a potential candidate for use in various energy storage devices.
In situ anodic electrodeposition of two-dimensional conductive metal-organic framework@nickel foam for high-performance flexible supercapacitor
Owing to their large specific surface area and well-defined porosity, metal-organic frameworks (MOFs) have long been considered as promising materials for energy storage. Unfortunately, their straightforward utilization in supercapacitors was hindered for years due to poor conductivity until the emergence of 2D conductive MOF materials. To date, several 2D conductive MOF-based supercapacitors have been reported. Nevertheless, almost all these supercapacitors were fabricated from MOF powders through a slurry coating method or dense packing method, which negatively affected their capacitor performance. Herein, we have developed an anodic electrodeposition (AED) approach to fabricate a uniformly deposited 2D conducting MOF on nickel foam and use it directly as electrodes for supercapacitors without any additives. Finally, the superior performance of the 2D conducting MOF on nickel foam in both aqueous and organic electrolytes was then disclosed by a series of electrochemical measurements, demonstrating the significant advantages of the AED approach over traditional methods.
High performance porous Si anode enabled by an organic-solvent assisted etching process
Silicon (Si) is a promising anode for the next generation of lithium-ion batteries, but its large volume changes (~300 %) during cycling hindered its practical applications. One method to improve its stability is to etch micron sized Si/SiO 2 particles to form porous Si (p-Si) and accommodate volume changes internally. However, the conventional HF etching method generates excess gas/heat and is difficult to scale up. Herein, we developed an organic-solvent-assisted HF etching process (O-HF) using a mixture of benzene and saturated HF aqueous solution. The organic solvent can be preferentially absorbed on the surface of Si/SiO 2 powder so etching rate of SiO 2 can be controlled to avoid rapid gas/heat generation. This method can also prevent over-etching of Si by minimizing direct contact/react between water and newly exposed Si. Si||NMC622 cells using carbon coated p-Si particles prepared by optimized O-HF etching process demonstrate a capacity retention of 82.0 % after 500 cycles, which is much better than those prepared by conventional HF etching (73.7 %). The thickness of Si anode increases only ~10 % during the initial lithiation, which is comparable with those of graphite anode. In conclusion, the O-HF etching strategy developed in this work can also be applied to the etching of a broad range of materials.
How to get noWear? – A new take on the design of in-situ formed high performing low-friction tribofilms
Not Available
Electrode Design with Integration of High Tortuosity and Sulfur-Philicity for High-Performance Lithium-Sulfur Battery
Not Available
High-performance methylammonium-free ideal-band-gap perovskite solar cells
Not Available
Observation of large Rashba spin–orbit coupling at room temperature in compositionally engineered perovskite single crystals and application in high performance photodetectors
Indirect absorption extended below the direct transition edge and increase in carrier lifetime derived from Rashba spin–orbit coupling may advance the optoelectronic applications of metal halide perovskites. Spin-orbit coupling in halide perovskites is due to the presence of heavy elements in their structure. However, when these materials lack an inversion symmetry, for example by the application of strain, spin–orbit coupling becomes odd in the electron’s momentum giving rise to a splitting in the electronic energy bands. Here we report on the observation of a large Rashba splitting of 117 meV at room temperature, as predicted by relativistic first-principles calculations, in halide perovskite single crystals through a facile compositional engineering approach. Partial substitution of organic cations by rubidium in single crystals induces significant indirect absorption and dual peak photoluminescence as a result of a large Rashba splitting. We measured circularly polarized photoluminescence and magneto-photoluminescence in perovskite films printed by single crystals as well as magneto-electroluminescence and magneto-photocurrent in spin-LEDs based on perovskite single crystals. They indicated significant spin-momentum locking due to the large Rashba effect. A hybrid perovskite single crystal photodetector achieved record figures of merit, including detectivity of more than 1.3 × 10 18 Jones which represents a three orders of magnitude improvement compared to the to date record. Furthermore, these findings show that facile compositional engineering of perovskite single crystals holds great promise for further advancing the optoelectronic properties of existing materials.
High-performance MFI zeolite hollow fiber membranes synthesized by double-layer seeding with variable temperature secondary growth
Not Available
High performance perovskites solar cells by hybrid perovskites co-crystallized with poly(ethylene oxide)
Abstract not provided
Spreading monoclinic boundary network between hexagonal primary grains for high performance Ni-rich
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