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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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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Pressure-Resistant Intermediate Valence in the Kondo Insulator SmB 6

Resonant x-ray emission spectroscopy was used to determine the pressure dependence of the f-electron occupancy in the Kondo insulator SmB 6 . Applied pressure reduces the f occupancy, but surprisingly, the material maintains a significant divalent character up to a pressure of at least 35 GPa. Thus, the closure of the resistive activation energy gap and onset of magnetic order are not driven by stabilization of an integer valent state. In conclusion, over the entire pressure range, the material maintains a remarkably stable intermediate valence that can in principle support a nontrivial band structure.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

“Ni-Less” Cathodes for High Energy Density, Intermediate Temperature Na-NiCl 2 Batteries

Among various battery technologies being considered for stationary energy storage applications, sodium-metal halide (Na-MH) batteries have become one of the most attractive candidates because of the abundance of raw materials, long cycle life, high energy density, and superior safety. However, one of issues limiting its practical application is the relatively expensive nickel (Ni) used in the cathode. In the present work, we focus on of efforts to develop new Ni-based cathodes, and demonstrate that a much higher specific energy density of 405 Wh/kg (23% higher than state-of-the-art Na-MH batteries) can be achieved at an operating temperature of 190oC. Furthermore, 15% less Ni is used in the new cathode than that in conventional Na-NiCl2 batteries. Long-term cycling tests also show stable electrochemical performance for over 300 cycles with excellent capacity retention (~100%). The results in this work indicate that these advances can significantly reduce the raw material cost associated with Ni (a 31% reduction) and promote practical applications of Na-MH battery technologies in stationary energy storage systems.

Chang, Hee-Jung↗
DOE OSTI2025

A new synthetic method of [Ru(2,2′:6′,2″-terpyridine)(2,2′-bipyridine)Cl] + complexes using cis -[Ru(2,2′:6′,2″-terpyridine)(NCCH 3 ) 2 Cl] + as an intermediate and comparison to a method using [Ru(benzene)(2,2′-bipyridine)Cl] + intermediates

A new method of synthesizing [Ru(terpy)(bpy)Cl] + (terpy = 2,2′:6′,2″-terpyridine, bpy = 2,2′-bipyridine) complexes using the starting material cis-[Ru(terpy)(NCCH 3 ) 2 Cl](PF 6 ) is reported. The yields of four derivatives ([Ru(terpy)(NN)Cl](PF 6 ): NN = bpy, 1; 4,4′-(MeO) 2 bpy, 2; 4,4′-(CF 3 ) 2 bpy, 3; 2,2′-biquinoline, 4) with this method range from 58 to 94 % and are similar to or greater than a known reaction in which the starting material is [Ru(benzene)(NN)Cl](PF 6 ). However, the use of cis-[Ru(terpy)(NCCH 3 ) 2 Cl](PF 6 ) results in lower levels of homoleptic Ru byproducts in the synthesis of 1 as compared to the use of [Ru(benzene)(bpy)Cl](PF 6 ) as determined by 1 H NMR spectroscopy. In addition, a high-purity and gram-scale synthesis of cis-[Ru(terpy)(NCCH 3 ) 2 Cl](PF 6 ) that does not use column chromatography is reported, in contrast to the original synthesis disclosed in the literature.

Bipyridine↗