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Hydrous hydrazine (N2H4∙H2O) is a candidate for a hydrogen carrier for storage and transportation due to low material cost, high hydrogen content of 8.0%, and liquid stability at room temperature. Pt and Pt nanoalloy catalysts have been welcomed by researchers for the dehydrogenation of hydrous hydrazine recently. Therefore, in this review, we give a summary of Pt nanoalloy catalysts for the dehydrogenation of hydrous hydrazine and briefly introduce the decomposition mechanism of hydrous hydrazine to prove the design principle of the catalyst. The chemical characteristics of hydrous hydrazine and the mechanism of dehydrogenation reaction are briefly introduced. The catalytic activity of hydrous hydrazine on different supports and the factors affecting the selectivity of hydrogen catalyzed by Ni-Pt are analyzed. It is expected to provide a new way for the development of high-activity catalysts for the dehydrogenation of hydrous hydrazine to produce hydrogen.

Hydrogen energy is considered to be a desired energy storage carrier because of its high-energy density, extensive sources, and is environmentally friendly. The development of hydrogen storage material, especially liquid organic hydrogen carrier (LOHC), has drawn intensive attention to address the problem of hydrogen utilization. Hydrogen carrier is a material that can reversibly absorb and release hydrogen using catalysts at elevated temperature, in which LOHC mainly relies on the covalent bonding of hydrogen during storage to facilitate long-distance transportation and treatment. In this review, the chemical properties and state-of-the-art of LOHCs were investigated and discussed. It reviews the latest research progress with regard to liquid organic hydrogen storage materials, namely N-ethylcarbazole, and the recent progress in the preparation of efficient catalysts for N-ethylcarbazole dehydrogenation by using metal multiphase catalysts supported by carbon–nitrogen materials is expounded. Several approaches have been considered to obtain efficient catalysts such as increasing the surface area of the support, optimizing particle size, and enhancing the porous structure of the support. This review provides a new direction for the research of hydrogen storage materials and considerations for follow-up research.

Bi-bearing Al-Ga-In-Sn quinary alloys were prepared by a high-temperature melting technique. The alloys primarily consist of Al(Ga) matrix and Ga, In, Sn, Bi (GISB) grain boundary phase, mainly in the form of Ga-InSn4-InBi. The microstructure of GISB particles was obviously equiaxed with the increasing Bi dosage. Al-water reaction was tested at 40 °C. Owing to the Bi-doping, the hydrogen generation yields of alloys with InSn4 intermetallic compound are obviously improved and hydrogen release rates gradually tend to be stable, which show great potential in applications. At the dosage of 2.53 wt% Bi, the hydrogen generation performance of alloys was more prominent in Al-water reaction, including a theoretical hydrogen generation yield and hydrogen released extremum rate to ∼0.076 L/min·g Al alloy. Furthermore, the Al-water reaction mechanism of Bi-bearing Al-rich low-In quinary alloys has been put forward.

Cu-containing Al-Ga-InSn4 quinary alloys were prepared by a simple smelting method under a high-purity nitrogen atmosphere, and the alloys were cast at room temperature. The microstructures were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy analysis. In addition to the InSn4 intermetallic compounds, elemental Cu was found in the alloys. As the Cu content increased, more holes and cracks were formed, and the Al(Ga) solid solution was pulverized. The melting points of Al compounds with the other elements were determined by differential scanning calorimetry (DSC). The alloy and water reactions were investigated at a water temperature of 40 °C. The Cu addition not only increased the hydrogen yield of the Al-Ga-InSn4 alloys but also stabilized the hydrogen generation from the Al-water reaction, which indicated that the Al-Ga-InSn4-Cu alloys are more suitable as fuel hydrogen sources for proton exchange membrane fuel cells. Based on the DSC and SEM with EDX studies, we propose the reasons for the changes in the Al-water reaction with the Cu addition.

The battery industry is constantly seeking to improve battery capacity, lifetime, and safety. Electrolytes are a key development focus in achieving these goals, as traditional carbonate-based electrolytes cause capacity fade and gassing through degradation processes, as well as representing a safety risk due to flammability. The release of gasses through electrolyte decomposition is a problem of prominent concern in the battery industry, due to the negative impact of gassing on cell safety and performance. Studies on battery gassing have been reported for a wide range of battery systems,1-3 but the mechanisms and conditions of gas release are complex and not fully understood. Gaining a greater understanding of gassing mechanisms, and the specific electrolyte components that cause them, will allow for precise design of battery electrolyte formulations that optimize performance and minimize gassing. In addition to understanding traditional electrolyte blends, the investigation of new electrolytes and additives is essential in developing low-gassing batteries. Organosilicon (OS) materials have been developed by Silatronix® as critical high stability additions to conventional carbonate electrolytes to enable next-generation Li-ion batteries. This novel organosilicon chemistry involves the merging of a silane with a Li+ coordinating functionality. For example, the OS3® solvent family contains a nitrile functionality. The adoption of new Li-ion battery electrolyte materials is driven by the desire to deploy higher energy density batteries capable of performing under broader operating conditions of temperature and voltage, and the design of OS solvents results in low molecular-weight molecules that have demonstrated superior thermal and electrochemical stability,4,5 as well as good safety properties with a high flash point and low vapor pressure. Silatronix® has conducted commercially relevant performance testing and fundamental mechanistic studies to investigate gassing phenomena in advanced Li-ion chemistries under both cycling and storage test conditions. In these studies, commercially relevant electrolytes were evaluated as well as electrolytes designed to specifically isolate the effect of selected electrolyte components, including OS3® and other industry-relevant solvents. The dependence of gassing on storage and voltage conditions was investigated, and connections between gas analysis and the electrode surface chemistry are also reported. Gas component analysis was performed with a calibrated dual-column GC-TCD, a similar analytical system to that utilized in previous studies,6 which provides excellent resolution and quantification of every gaseous product. Key experimental results show that all OS3® concentrations reduce gas generation after 60°C storage and higher OS3® content provides greater benefit. Overall, we show that organosilicon additives substantially reduce gassing from carbonate-based electrolytes while maintaining good cell performance. Zhang, S.S., Insight into the Gassing Problem of Li-ion Battery. Frontiers in Energy Research 2014, 2, 59. Self, J.; Aiken, C.P.; Petibon, R.; Dahn, J.R., Survey of Gas Expansion in Li-Ion NMC Pouch Cells. Journal of the Electrochemical Society 2015, 162, A796-A802. Jung, R.; Metzger, M.; Maglia, F.; Stinner, C., Chemical vs Electrochemical Electrolyte Oxidation on NMC111, NMC622, LNMO, and Conductive Carbon. The Journal of Physical Chemistry Letters 2017, 8, 4820-4825. Guillot, S.L.; Peña-Hueso, A.; Usrey, M.; Hamers, R.J., Thermal and Hydrolytic Decomposition Mechanisms of Organosilicon Electrolytes with Enhanced Thermal Stability for Lithium-Ion batteries. Journal of the Electrochemical Society 2018, 164, A1907-A1917. Chen, X.; Usrey, M.; Peña-Hueso, A.; West, R.; Hamers, R.J., Thermal and Electrochemical Stability of Organosilicon Electrolytes for Lithium-Ion Batteries. Journal of Power Sources 2013, 241, 311-319. Xiong, D.J.; Ellis, L.D.; Petibon, R.; Hynes, T.; Liu, Q.Q.; Dahn, J.R., Studies of Gas Generation, Gas Consumption and Impedance Growth in Li-Ion Cells with Carbonate or Fluorinated Electrolytes Using the Pouch Bag Method. Journal of the Electrochemical Society 2017, 164, A340-A347.

A novel series of lithium alkyl trimethyl borates and lithium aryl trimethyl borates have been prepared and investigated as cathode film forming additives. The borates are prepared via the reaction of lithium alkoxides or lithium phenoxides with trimethyl borate. Incorporation of 0.5–2.0% (wt) of the lithium borates to a baseline electrolyte (1.0 M LiPF6 in 3 : 7 (EC/EMC)) results in improved capacity retention and efficiency of high voltage graphite/LiNi0.5Mn1.5O4 cells especially upon cycling at elevated temperature (55 °C). The improved performance results from the sacrificial oxidation of the lithium borate on the cathode surface to generate a cathode passivation film. The lithium borates can be readily structurally modified to act as a functional group delivery agent to modify the cathode surface. Ex situ surface analysis of the electrodes after cycling confirms that the lithium borates modify the cathode surface and generate a borate rich surface film which inhibits electrolyte oxidation and Mn dissolution.

Adsorption energies, structural properties and electronic structures of atomic bromine adsorbed in on-surface sites on Mg(0 0 0 1) surface were investigated by using the density functional theory. Bromine coverages varying from 0.25 to 1.00 monolayer were considered. The most stable on-surface adsorption site is the fcc-hollow site in the whole coverage range. When the coverage increases, the adsorption energy decreases and the work function increases. On-surface bromine induces a contraction of the distance between the topmost and second Mg layers. The relative stability of surfaces with different Br coverages depends on the bromine chemical potential was analyzed, and the result suggests that bromine atom easily adsorbs on Mg(0 0 0 1) surface and the bulk MgBr 2 is energetically competitive. A comparison of the adsorbed F, Cl and Br on the Mg(0 0 0 1) surface was further investigated.

Lithium tetramethyl borate (LTMB, LiB(OCH3)4) has been prepared and investigated as a novel cathode film forming additive to improve the performance of LiNi0.5Mn1.5O4 cathodes cycled to high potential (4.25-4.8 V). Addition of LTMB to 1.2 M LiPF6 in EC/EMC (3/7, v/v) improves the capacity retention of graphite/LiNi0.5Mn1.5O4 cells cycled at 55◦C. The added LTMB is sacrificially oxidized on the surface of the cathode during the first charging cycle. Ex-situ surface analysis of the LiNi0.5Mn1.5O4 by X-ray photoelectron spectroscopy (XPS) reveals the presence of a borate based passivating layer which appears to inhibit electrolyte oxidation on the cathode surface. © The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. [DOI: 10.1149/2.0021508eel] All rights reserved.

A new copper-catalyzed regioselective cross-dehydrogenative coupling of coumarins with benzylic Csp3–H bonds has been developed. This reaction provides direct access to a wide range of 3-benzylcoumarins in moderate to good yields. The protocol was also extended successfully to other heterocyclic compounds, such as quinolinones.

Visible-light-initiated homogeneous oxidative synthesis of nitriles from amines was accomplished through a combined use of photoredox and copper catalysis. This transformation was performed at room temperature with O2 as the oxidant.

Radically changing benzyls: An efficient method for the benzylarylation of activated alkenes has been developed through a copper-catalyzed tandem radical addition/cyclization strategy (see scheme). This oxidative coupling between acrylamides and benzylic hydrocarbons provides access to diverse alkyl-substituted oxindoles in good to excellent yields. A variety of functional groups were tolerated in this transformation (TBPB = tert-butylperoxy benzoate).

Methyl butyrate (MB) has been investigated as a co-solvent for lithium-ion battery electrolytes to improve the performance at low temperature (−10 to −30 °C). The cycling performance of graphite/LiNi1/3Co1/3Mn1/3O2 cells with 1.2 M lithium tetrafluorooxalatophosphate (LiFOP) in 2:2:6 EC/EMC/MB was compared to 1.2 M LiPF6 in both 3:7 EC/EMC and 2:2:6 EC/EMC/MB. The LiFOP/MB electrolyte has a good operational temperature window and comparable cycling performance to the LiPF6 electrolyte at both room temperature and low temperature (−10 °C). However, after accelerated aging the LiFOP/MB electrolyte has worse performance at very low temperature (−30 °C) compared to LiPF6 electrolytes. Ex-situ surface analysis was conducted by scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transfer infrared spectroscopy to provide insight into the performance differences.

The cycling performance of LiPF 4 (C 2 O 4 ) (LiFOP) electrolyte with propylene carbonate (PC) as a cosolvent is compared with LiPF 6 electrolyte with ethylene carbonate (EC) as a cosolvent in the presence of different cathode materials, such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 and LiFePO 4 . The cycling performance of cells with LiFOP and PC is similar to cells with LiPF 6 with EC at room temperature and superior at low temperature (−10 °C). After thermal abuse the room temperature performance of cells with LiFOP electrolyte and PC is worse than cells with LiPF 6 and EC. A detailed analysis of the surface films on both the anode and the cathode via X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Fourier transfer infrared spectroscopy (FT-IR) in the attenuated total reflection (ATR) mode was conducted to provide a better understanding of performance differences.

The cycling performance of LiPF4(C2O4) electrolyte is compared with LiPF6 electrolyte in the presence of several different electrode materials. The cycling of MCMB/LiNi1/3Co1/3Mn1/3O2 and natural graphite/LiFePO4 cells provides very similar performance for both electrolytes. However, MCMB/LiMn2O4 cells have a lower initial reversible capacity with LiPF4(C2O4) electrolytes. A detailed analysis of the surface films on both the cathode and the anode via X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) was conducted. The performance differences are attributed to the anode as opposed to the cathode.

A hierarchical porous carbon with low oxygen content has been prepared by using polystyrene (PS) spheres as template and its structure, composition and performances as anode of lithium ion battery are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, element analysis (EA), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge test. The results obtained from SEM, TEM, XRD, FTIR, and EA indicate that the prepared sample has a well-interconnected pore structure with a pore size of 170 nm and has an oxygen content of 3.3 ± 0.2 wt.%. The low oxygen content of the prepared sample can be ascribed to the low decomposition temperature of the template that was determined by thermal analysis. EIS shows that the prepared sample has lower electrochemical impedance for the lithium insertion/de-insertion than commercial natural graphite and charge/discharge tests show that the battery using the prepared sample as anode exhibits better rate performance than that using the graphite.

Lithium difluoro (oxalate) borate (LiDFOB) is used as thermal stabilizing and solid electrolyte interface (SEI) formation additive for lithium-ion battery. The enhancements of electrolyte thermal stability and the SEIs on graphite anode and LiFePO4 cathode with LiDFOB addition are investigated via a combination of electrochemical methods, nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared-attenuated total reflectance (FTIR-ATR), as well as density functional theory (DFT). It is found that cells with electrolyte containing 5% LiDFOB have better capacity retention than cells without LiDFOB. This improved performance is ascribed to the assistance of LiDFOB in forming better SEIs on anode and cathode and also the enhancement of the thermal stability of the electrolyte. LiDFOB-decomposition products are identified experimentally on the surface of the anode and cathode and supported by theoretical calculations.

The novel electrolyte, lithium tetrafluorooxalatophosphate (LiPF4(C2O4)), was investigated with various electrodes (graphite, LiNi1/3Co1/3Mn1/3O2, LiFePO4 and LiMn2O4). The room temperature cycling performance of LiPF4(C2O4) is compared to LiPF6 electrolytes.

A new gel polymer electrolyte (GPE) is reported in this paper. In this GPE, blending polymer of poly(ethylene oxide) (PEO) with poly(vinylidene fluoride-hexafluoropropylene) (P(VdF-HFP)), doped with nano-Al2O3 and supported by polypropylene (PP), is used as polymer matrix, namely PEO–P(VdF-HFP)–Al2O3/PP. The performances of the PEO–P(VdF-HFP)–Al2O3/PP membrane and the corresponding GPE are characterized with mechanical test, CA, EIS, TGA and charge–discharge test. It is found that the performances of the membrane and the GPE depend to a great extent on the content of doped nano-Al2O3. With doping 10 wt.% nano-Al2O3 in PEO–P(VdF-HFP), the mechanical strength from 9.3 MPa to 14.3 MPa, the porosity of the membrane increases from 42% to 49%, the electrolyte uptake from 176% to 273%, the thermal decomposition temperature from 225 °C to 355 °C, and the ionic conductivity of corresponding GPE is improved from 2.7 × 10−3 S cm−1 to 3.8 × 10−3 S cm−1. The lithium ion battery using this GPE exhibits good rate and cycle performances.

4,5-Dimethyl-[1,3]dioxol-2-one (DMDO) was used as a novel electrolyte additive for lithium-ion batteries. The effect of DMDO on the formation of the solid electrolyte interface (SEI) on anode and cathode of MCMB/LiNi0.8Co0.2O2 cells was investigated via a combination of electrochemical methods, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations. It is found that cells with electrolyte containing 2% DMDO have better capacity retention than cells without DMDO and this improved performance is ascribed to the assistance of DMDO in forming better SEIs on anode and cathode. DMDO-decomposition products are identified experimentally on the surface of the anode and cathode and supported by theoretical calculations.

Catalytic electrolysis of ammonia provides a promising technique for generation of hydrogen and, simultaneously, maintenance of environmental sustainability. In this work, the electro-oxidation of ammonia on platinum (Pt) electrode was systematically studied in alkaline solution by cyclic voltammetry. The effects of operating conditions and the electrochemical test parameters, such as ammonia concentration, KOH concentration, electrode rotating speed, temperature, upper switch potential, potential sweep rate and cyclic number, on the ammonia oxidation and hydrogen evolution were investigated. The ammonia oxidation on Pt electrode is controlled by mass-transfer process of ammonia towards the electrode surface. However, the adsorption and desorption of NxHy intermediates play important roles in ammonia oxidation and hydrogen evolution. Determination of the ammonia electro-oxidation kinetics depends on a comprehensive consideration of mass-transfer and adsorption/desorption processes. There is an optimal ammonia concentration and KOH concentration to maximize the ammonia oxidation and hydrogen evolution simultaneously. The ammonia electro-oxidation current decreases with the increasing electrode rotating speed, and increases with the elevated temperature. The cell efficiency for ammonia electrolysis on Pt electrode can be up to 45%. Increasing ammonia and KOH concentrations could increase the electrolytic cell efficiency slightly.

Platinum (Pt) black electrode was fabricated by electrolytic deposition for oxidation of ammonia. The electrocatalytic activity of the fabricated platinum black was characterized by cyclic voltammetry and atomic force microscopy observation. Pt black electrocatalyst enhances significantly the electro-oxidation of ammonia. The increased catalytic activity of Pt black electrode is attributable to both an increased effective surface area and the enhanced electron transfer reaction. However, the latter is predominant throughout the ammonia oxidation processes. The electrolytic depositing parameters affect the electrocatalytic activity of Pt black electrode. In particular, there is an optimal depositing potential to maximize the electrocatalytic activity. With the increasing depositing time and elevated bath temperature, the electrocatalytic activity of Pt black electrode increases continuously in this work.

In order to deepen the understanding of the relationship between fundamental properties (including: microstructure and composition) and photocatalytic performance, four bismuthate compounds, including: LiBiO3, NaBiO3, KBiO3, and AgBiO3, are regarded as research examples in the present work, because they have particular crystal structures and similar compositions. Using density functional theory calculations, their structural, electronic, and optical properties are investigated and compared systematically. First of all, the calculated results of crystal structures and optical properties are in agreement with available published experimental data. Based on the calculated results, it is found that the tunneled or layered micro-structural properties lead to the stronger interaction between bismuth and oxygen, and the weaker interaction between alkaline-earth metal and [BiO6] octahedron, resulting in the feature of multi-band gaps in the cases of LiBiO3, NaBiO3, and KBiO3. This conclusion is supported by the case of AgBiO3, in which the feature of multi-band gaps disappears, due to the stronger interaction between the noble metal and [BiO6] octahedron. These properties have significant advantages in the photocatalytic performance: absorbing low energy photons, rapidly transferring energy carriers. Furthermore, the features of electronic structures of bismuthate compounds are well reflected by the absorption spectra, which could be confirmed by experimental measurements in practice. Combined with the calculated results, it could be considered that the crystal structures and compositions of the photocatalyst determine the electronic structures and optical properties, and subsequently determine the corresponding photocatalytic performance. Thus, a novel Bi-based photocatalyst driven by visible-light could be designed by utilizing specific compositions to form favorable electronic structures or specific micro-structures to form a beneficial channel for energy carriers.

A novel nonflammable electrolyte for lithium-ion batteries has been developed. The optimized electrolyte is composed of LiPF 6 in a mixture of carbonate solvents with added dimethyl methylphosphonate as a flame retarding cosolvent and lithium bis(oxalatoborate) as an anode film forming additive. Conductivity, thermal stability, electrochemical stability, self extinguishing times, electrochemical cycling, and ex situ surface analysis of the cycled electrodes are reported. This novel electrolyte has a comparable cycling efficiency to the current state-of-the-art electrolytes for lithium-ion batteries but is nonflammable.