Pseudo-Binary Phase Diagram of LiNH2-MH (M = Na, K) Eutectic Mixture.

The hunt for a cleaner energy carrier leads us to consider a source that produces no toxic byproducts. One of the targeted alternatives in this approach is hydrogen energy, which, unfortunately, suffers from a lack of efficient storage media. Solid-state hydrogen absorption systems, such as lithium amide (LiNH2) systems, may store up to 6.5 weight percent hydrogen. However, the temperature of hydrogenation and dehydrogenation is too high for practical use. Various molar ratios of LiNH2 with sodium hydride (NaH) and potassium hydride (KH) have been explored in this paper. The temperature of hydrogenation for LiNH2 combined with KH and NaH was found to be substantially lower than the temperature of individual LiNH2. This lower temperature operation of both LiNH2-NaH and LiNH2-KH systems was investigated in depth, and the eutectic melting phenomenon was observed. Systematic thermal studies of this amide-hydride system in different compositions were carried out, which enabled the plotting of a pseudo-binary phase diagram. The occurrence of eutectic interaction increased atomic mobility, which resulted in the kinetic modification followed by an increase in the reactivity of two materials. For these eutectic compositions, i.e., 0.15LiNH2-0.85NaH and 0.25LiNH2-0.75KH, the lowest melting temperature was found to be 307 °C and 235 °C, respectively. Morphological studies were used to investigate and present the detailed mechanism linked with this phenomenon.

Implementation of Bismuth Chalcogenides as an Efficient Anode: A Journey from Conventional Liquid Electrolyte to an All-Solid-State Li-Ion Battery.

Bismuth chalcogenide (Bi2X3; X = sulfur (S), selenium (Se), and tellurium (Te)) materials are considered as promising materials for diverse applications due to their unique properties. Their narrow bandgap, good thermal conductivity, and environmental friendliness make them suitable candidates for thermoelectric applications, photodetector, sensors along with a wide array of energy storage applications. More specifically, their unique layered structure allows them to intercalate Li+ ions and further provide conducting channels for transport. This property makes these suitable anodes for Li-ion batteries. However, low conductivity and high-volume expansion cause the poor electrochemical cyclability, thus creating a bottleneck to the implementation of these for practical use. Tremendous endeavors have been devoted towards the enhancement of cyclability of these materials, including nanostructuring and the incorporation of a carbon framework matrix to immobilize the nanostructures to prevent agglomeration. Apart from all these techniques to improve the anode properties of Bi2X3 materials, a step towards all-solid-state lithium-ion batteries using Bi2X3-based anodes has also been proven as a key approach for next-generation batteries. This review article highlights the main issues and recent advances associated with Bi2X3 anodes using both solid and liquid electrolytes.

XPS Investigation on Improving Hydrogen Sorption Kinetics of the KSiH3 System by Using Zr-Based Catalysts.

The superior hydrogen storage properties makes the KSiH3 system a potential hydrogen storage material for practical applications. A theoretical capacity of 4.3 wt% bring this material to the front line of all the available hydrogen storage materials; however, the activation barrier of the reaction restricts the system to absorb and desorb hydrogen reversibly at elevated temperatures even if the thermodynamics suggest its room temperature operation. Several catalysts have already been tested to enhance its kinetic properties. In this work, the efforts were made to reduce the activation energy by using Zr-based catalysts to the KSi/KSiH3 system. The value of activation energy was found to be lowest (i.e., 87 kJ mol-1) for the ZrH2-added KSiH3 system. The mechanism of this improvement was investigated by using X-ray photoelectron spectroscopy (XPS).