scholarly journals Transformation of Ammonium Azide at High Pressure and Temperature

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4102
Author(s):  
Guozhao Zhang ◽  
Haiwa Zhang ◽  
Sandra Ninet ◽  
Hongyang Zhu ◽  
Keevin Beneut ◽  
...  
Keyword(s):  
High Pressure ◽  
Room Temperature ◽  
High Energy ◽  
High Energy Density ◽  
X Ray Diffraction ◽  
Polymeric Compound ◽  
High Pressure And Temperature ◽  
Polynitrogen Compounds ◽  
Vibrational Features ◽  
Solid Ammonia

The compression of ammonium azide (AA) has been considered to be a promising route for producing high energy-density polynitrogen compounds. So far though, there is no experimental evidence that pure AA can be transformed into polynitrogen materials under high pressure at room temperature. We report here on high pressure (P) and temperature (T) experiments on AA embedded in N2 and on pure AA in the range 0–30 GPa, 300–700 K. The decomposition of AA into N2 and NH3 was observed in liquid N2 around 15 GPa–700 K. For pressures above 20 GPa, our results show that AA in N2 transforms into a new crystalline compound and solid ammonia when heated above 620 K. This compound is stable at room temperature and on decompression down to at least 7.0 GPa. Pure AA also transforms into a new compound at similar P–T conditions, but the product is different. The newly observed phases are studied by Raman spectroscopy and X-ray diffraction and compared to nitrogen and hydronitrogen compounds that have been predicted in the literature. While there is no exact match with any of them, similar vibrational features are found between the product that was obtained in AA + N2 with a polymeric compound of N9H formula.

Formation of cubic C-BN by crystallization of nano-amorphous solid at atmosphere

1998 ◽  
Vol 13 (7) ◽  
pp. 1753-1756 ◽  
Author(s):  
Bin Yao ◽  
L. Liu ◽  
W. H. Su
Keyword(s):  
Solid Solution ◽  
Grain Size ◽  
High Pressure ◽  
Boron Nitride ◽  
Amorphous Carbon ◽  
Solid Solutions ◽  
Room Temperature ◽  
Amorphous Solid ◽  
High Energy ◽  
High Pressure And Temperature

An amorphous carbon-boron nitride (C-BN) solid was prepared by ball milling the mixture of graphite and hexagonal BN powders for a period of 120 h. After annealing the amorphous C-BN solid for 1 h at atmosphere in the temperature range from 800 to 900 K and then quenching it to room temperature, a small amount of cubic C-BN solid solutions with diamond-like structure, which belong to a high energy phase and can only be synthesized previously under high pressure and temperature (30 GPa, 2000 K), were observed in the annealed amorphous C-BN solid. The lattice constant of the cubic C-BN solid solution was 0.3587 nm, and its grain size was in the range of 10 to 50 nm.

Lithium superionic conductors Li10MP2O12 (M = Ge, Si)

2018 ◽  
Vol 11 (02) ◽  
pp. 1850039 ◽  
Author(s):  
Shufeng Song ◽  
Zhencai Dong ◽  
Fan Deng ◽  
Ning Hu
Keyword(s):  
Room Temperature ◽  
High Energy ◽  
High Energy Density ◽  
Superionic Conductors ◽  
X Ray Diffraction ◽  
Melt Quenching ◽  
Lithium Ions ◽  
X Ray ◽  
Migration Mechanism ◽  
Dc Polarization

The exploration for superionic conductors with new structures and compositions is challengeable for developing safer and high-energy-density batteries. Here, we report lithium superionic conductors with the compositions of Li[Formula: see text]GeP2O[Formula: see text] and Li[Formula: see text]SiP2O[Formula: see text]. The materials are prepared by melt-quenching and characterized by X-ray diffraction (XRD), AC impedance, DC polarization and cyclic voltammetry. Both germanium and silicon members demonstrate same orders of magnitude of bulk and grain-boundary conductivities of 10[Formula: see text] S[Formula: see text]cm[Formula: see text] at room temperature. The crystal structure is investigated by the Rietveld refinement of powder XRD and the migration mechanism of lithium ions is proposed.

scholarly journals Synthesis of magnesium-nitrogen salts of polynitrogen anions

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Dominique Laniel ◽  
Bjoern Winkler ◽  
Egor Koemets ◽  
Timofey Fedotenko ◽  
Maxim Bykov ◽  
...  
Keyword(s):  
High Pressures ◽  
Molecular Nitrogen ◽  
High Energy ◽  
High Energy Density ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Energy Density Materials ◽  
Polynitrogen Compounds ◽  
Laser Heated

Abstract The synthesis of polynitrogen compounds is of fundamental importance due to their potential as environmentally-friendly high energy density materials. Attesting to the intrinsic difficulties related to their formation, only three polynitrogen ions, bulk stabilized as salts, are known. Here, magnesium and molecular nitrogen are compressed to about 50 GPa and laser-heated, producing two chemically simple salts of polynitrogen anions, MgN4 and Mg2N4. Single-crystal X-ray diffraction reveals infinite anionic polythiazyl-like 1D N-N chains in the crystal structure of MgN4 and cis-tetranitrogen N44− units in the two isosymmetric polymorphs of Mg2N4. The cis-tetranitrogen units are found to be recoverable at atmospheric pressure. Our results respond to the quest for polynitrogen entities stable at ambient conditions, reveal the potential of employing high pressures in their synthesis and enrich the nitrogen chemistry through the discovery of other nitrogen species, which provides further possibilities to design improved polynitrogen arrangements.

scholarly journals Research Progress toward Room Temperature Sodium Sulfur Batteries: A Review

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1535
Author(s):  
Yanjie Wang ◽  
Yingjie Zhang ◽  
Hongyu Cheng ◽  
Zhicong Ni ◽  
Ying Wang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Room Temperature ◽  
High Energy ◽  
Safety Performance ◽  
High Energy Density ◽  
Research Progress ◽  
Storage Performance ◽  
Sulfur Battery ◽  
Sodium Sulfur Battery ◽  
Sodium Sulfur

Lithium metal batteries have achieved large-scale application, but still have limitations such as poor safety performance and high cost, and limited lithium resources limit the production of lithium batteries. The construction of these devices is also hampered by limited lithium supplies. Therefore, it is particularly important to find alternative metals for lithium replacement. Sodium has the properties of rich in content, low cost and ability to provide high voltage, which makes it an ideal substitute for lithium. Sulfur-based materials have attributes of high energy density, high theoretical specific capacity and are easily oxidized. They may be used as cathodes matched with sodium anodes to form a sodium-sulfur battery. Traditional sodium-sulfur batteries are used at a temperature of about 300 °C. In order to solve problems associated with flammability, explosiveness and energy loss caused by high-temperature use conditions, most research is now focused on the development of room temperature sodium-sulfur batteries. Regardless of safety performance or energy storage performance, room temperature sodium-sulfur batteries have great potential as next-generation secondary batteries. This article summarizes the working principle and existing problems for room temperature sodium-sulfur battery, and summarizes the methods necessary to solve key scientific problems to improve the comprehensive energy storage performance of sodium-sulfur battery from four aspects: cathode, anode, electrolyte and separator.

scholarly journals Monocarborane cluster as a stable fluorine-free calcium battery electrolyte

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kazuaki Kisu ◽  
Sangryun Kim ◽  
Takara Shinohara ◽  
Kun Zhao ◽  
Andreas Züttel ◽  
...  
Keyword(s):  
Room Temperature ◽  
Coulombic Efficiency ◽  
Low Cost ◽  
Ionic Conductivities ◽  
High Energy ◽  
High Energy Density ◽  
Free Calcium ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Battery Electrolyte

AbstractHigh-energy-density and low-cost calcium (Ca) batteries have been proposed as ‘beyond-Li-ion’ electrochemical energy storage devices. However, they have seen limited progress due to challenges associated with developing electrolytes showing reductive/oxidative stabilities and high ionic conductivities. This paper describes a calcium monocarborane cluster salt in a mixed solvent as a Ca-battery electrolyte with high anodic stability (up to 4 V vs. Ca2+/Ca), high ionic conductivity (4 mS cm−1), and high Coulombic efficiency for Ca plating/stripping at room temperature. The developed electrolyte is a promising candidate for use in room-temperature rechargeable Ca batteries.

Microstructure Evolution of a Fine Grain Al-50wt%Si Alloy Fabricated by High Energy Milling

2011 ◽  
Vol 479 ◽  
pp. 54-61 ◽  
Author(s):  
Fei Wang ◽  
Ya Ping Wang
Keyword(s):  
Grain Growth ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Milling Time ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Laser Method ◽  
X Ray ◽  
Fine Grain

Microstructure evolution of high energy milled Al-50wt%Si alloy during heat treatment at different temperature was studied. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results show that the size of the alloy powders decreased with increasing milling time. The observable coarsening of Si particles was not seen below 730°C in the high energy milled alloy, whereas, for the alloy prepared by mixed Al and Si powders, the grain growth occurred at 660°C. The activation energy for the grain growth of Si particles in the high energy milled alloy was determined as about 244 kJ/mol by the differential scanning calorimetry (DSC) data analysis. The size of Si particles in the hot pressed Al-50wt%Si alloy prepared by high energy milled powders was 5-30 m at 700°C, which was significantly reduced compared to that of the original Si powders. Thermal diffusivity of the hot pressed Al-50wt%Si alloy was 55 mm2/s at room temperature which was obtained by laser method.

scholarly journals High-performance room-temperature sodium–sulfur battery enabled by electrocatalytic sodium polysulfides full conversion

2020 ◽  
Vol 13 (2) ◽  
pp. 562-570 ◽  
Author(s):  
Nana Wang ◽  
Yunxiao Wang ◽  
Zhongchao Bai ◽  
Zhiwei Fang ◽  
Xiao Zhang ◽  
...  
Keyword(s):  
Energy Density ◽  
High Performance ◽  
Room Temperature ◽  
Gold Nanoclusters ◽  
High Energy ◽  
High Energy Density ◽  
Sulfur Battery ◽  
Sodium Sulfur Battery ◽  
Sodium Sulfur ◽  
Full Conversion

Developing novel gold nanoclusters as an electrocatalyst can facilitate a completely reversible reaction between S and Na, achieving advanced high-energy-density room-temperature sodium–sulfur batteries.

Core–Shell Fe1–[email protected] Nanorods for Room Temperature All-Solid-State Sodium Batteries with High Energy Density

ACS Nano ◽  
2018 ◽  
Vol 12 (3) ◽  
pp. 2809-2817 ◽  
Author(s):  
Hongli Wan ◽  
Jean Pierre Mwizerwa ◽  
Xingguo Qi ◽  
Xin Liu ◽  
Xiaoxiong Xu ◽  
...  
Keyword(s):  
Solid State ◽  
Energy Density ◽  
Room Temperature ◽  
High Energy ◽  
High Energy Density ◽  
Core Shell ◽  
Sodium Batteries
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