Lithium Nitride CAS 26134-62-3

Lithium nitride is a fast ion conductor with higher conductivity than other inorganic lithium salts. Many studies have focused on the application of lithium ntride as a solid electrode and cathode material for batteries.
A series of lithium fast ion conductors were prepared based on lithium ntride. Analyze and identify their phase composition, study their electrochemical properties such as ion conductivity, decomposition voltage, and conductivity, and assemble experimental batteries with these materials for discharge tests.

Research has shown that the lithium ntride based binary system (Li3N LiCl) has formed Li9N2Cl3 compounds, with a decomposition voltage of over 2.5V and a conductivity of 1.3 × 10-5 S cm-1 at 25 ℃. As a fast ion conductor material, it should have high decomposition voltage, low electronic conductivity, high ionic conductivity, and good chemical stability. Many fast ion conductors of lithium have the above characteristics, which can be used to manufacture high-performance all solid state batteries, used as power sources for calculators, camera flashes, electronic watches, and an increasing number of electronic devices and products; In addition, lithium-ion conductors can also be used to manufacture special ion devices.

People once imagined using lithium fast ion conductor materials to build large energy storage (electricity) piles. During the low peak period of electricity consumption in big cities at night, excess electricity could be charged into energy storage stations, and during the peak period of electricity consumption, it could continuously supply power to the grid. Due to the broad application prospects of lithium fast ion conductors, it has aroused great interest and extensive and in-depth research has been carried out to find better lithium fast ion conductors.

The decomposition voltage of Li3N is only 0.44V (25 ℃), which limits its practical application. Therefore, it is necessary to modify and synthesize Li3N based binary and ternary ion conductor materials. One improvement method is to mix the ground Li3N powder with an appropriate amount of anhydrous LiCl powder (2:3 molar ratio) evenly, press the tablets on a tablet press, load them into a nickel boat, place them in a synthesis device, use nitrogen as a protective atmosphere, heat to 600 ℃ (90 minutes), and obtain a gray white Li9N2Cl3 solid powder. From the study of electrochemical experiments, it was found that the decomposition voltage of Li9N2Cl3 compound prepared by adding LiCl to Li3N increased from 0.4V to over 2.5V.

In addition to being used as a solid electrolyte, lithium nitride is also an effective catalyst for the conversion of hexagonal boron nitride to cubic boron nitride.
In 1987, Japanese scholars used the seed crystal method under ultra-high pressure and high temperature conditions to obtain N-type cBN single crystals with a particle size of 2mm and irregular shape by doping Si. Then, they grew P-type cBN single crystals doped with Be on the surface of the crystal under secondary high pressure, and finally obtained cBN homogeneous P-N junctions by cutting and grinding. There are similar synthesis experiments in China, which were conducted on the domestically produced DS-029B six sided top press machine.

In order to investigate the effect of catalysts/additives on the shape of high-pressure synthesized cBN samples, the experiment used hBN with a purity of 99% as the initial raw material, self-made lithium ntride Li3N and lithium hydride LiH as catalysts, and commercial 99% purity amino lithium LiNH2 as an additive. Before the experiment, hexagonal boron nitride (hBN) was first dried at 100 ℃ for 12 hours under vacuum conditions to remove adsorbed moisture and gases from the raw materials. Then, the initial hBN was uniformly mixed with LiH, Li3N, LiH+Li3N, LiH+LiNH2, and Li3N+LiNH2 in a certain proportion, and pressed into a cylindrical shape with a diameter of 15.3mm and a height of 6mm.

 The synthesis pressure used in the experiment is 4.0-6.0 GPa, the temperature is 1400-1900 ℃, and the holding time is 10-20 minutes. After the experiment, slowly release the pressure, take out the sample for acid and alkali treatment, rinse and filter to obtain cBN crystals.

In addition to the above experiments, based on the traditional phase transition method, cubic boron nitride was synthesized by studying the use of lithium ntride as a catalyst, hexagonal boron nitride as a raw material, and adding different additives. By using X-ray diffraction technology, Raman diffraction technology, and other techniques to analyze and characterize the experimental products, it can be concluded that different additives will have different effects on the system.

The influence of ammonia fluoride on the synthesis of cubic boron nitride from lithium ntride and hexagonal boron nitride systems was analyzed. using X-ray diffraction technology to analyze the synthesized products, it was found that although ammonia fluoride consumes the catalyst lithium ntride, it also produces additional product ammonia gas, which can reduce the pressure of the synthesis experiment. Analyzing the effect of lithium hydride on the synthesis of cubic boron nitride from lithium ntride and hexagonal boron nitride systems, X-ray diffraction and Raman diffraction techniques were used to analyze the synthesized products.

It was found that lithium hydride reacts with hexagonal boron nitride to generate catalytic lithium ntride, ammonia gas, and elemental boron atoms. Elemental boron atoms have the effect of blackening the crystal color and inhibiting crystal growth along the (111) plane. The influence of catalyst assembly on the synthesis results can be discussed as follows: If it is considered that the formation process of cubic boron nitride first involves the diffusion reaction of catalyst into adjacent hexagonal boron nitride under high temperature and pressure, resulting in the formation of some intermediate compound.

The latter can dissolve the remaining hexagonal boron nitride and become a solvent melt. As the temperature and pressure enter the stable zone of cubic boron nitride, the dissolved nitrogen boron ions in the melt may exist individually or more likely in some group form. Due to the concentration reaching supersaturation, they will crystallize and precipitate according to the structure of cubic boron nitride. As these ions or ion groups continuously diffuse and deposit onto the precipitated cubic boron nitride crystals through the solvent melt, the crystals will continue to grow until the process stops.

Organic Light Emitting Devices (OLEDs) have solid-state, active emission properties
Due to its wide viewing angle, fast response speed (<1 μ s), wide operating temperature range (-45 ℃~+85 ℃), ability to be fabricated on flexible substrates, and low unit power consumption, it is regarded as one of the mainstream display and lighting technologies of the next generation in the industry. The application of various new organic semiconductor materials and new organic device structures has made significant progress in OLED performance and industrialization.

Due to the fact that the lowest unoccupied molecular orbital (LUMO) energy level of electronic transport materials in OLEDs is approximately 3eV, the corresponding organic n-dopant materials are difficult to find, and even if found, they are often unstable in air. Therefore, they need to be placed in a protective gas during material synthesis and device fabrication. Therefore, inorganic dopant materials are often used for n-type doping of organic semiconductor materials, such as metal lithium and metal cesium, which are applied in n-type doping of OLEDs. Later, some Li and Cs compound materials are also used as n-type dopants. However, the development of n-type doping in organic semiconductor materials still lags behind that of p-type doping. Therefore, the search for new n-type dopant materials to improve the effect of n-type doping is extremely urgent.