Performance Study of MXene/Carbon Nanotube Composites for Current Collector- and Binder-Free Mg-S Batteries.

The realization of sustainable and cheap Mg-S batteries depends on significant improvements in cycling stability. Building on the immense research on cathode optimization from Li-S batteries, for the first time a beneficial role of MXenes for Mg-S batteries is reported. Through a facile, low-temperature vacuum-filtration technique, several novel current collector- and binder-free cathode films were developed, with either dipenthamethylene thiuram tetrasulfide (PMTT) or S nanoparticles as the source of redox-active sulfur.

Highly conductive anion exchange membranes based on polymer networks containing imidazolium functionalised side chains.

Two novel types of anion exchange membranes (AEMs) having imidazolium-type functionalised nanofibrous substrates were prepared using the facile and potentially scalable method. The membranes' precursors were prepared by graft copolymerization of vinylbenzyl chloride (VBC) onto syndiotactic polypropylene (syn-PP) and polyamide-66 (PA-66) nanofibrous networks followed by crosslinking with 1,8-octanediamine, thermal treatment and subsequent functionalisation of imidazolium groups. The obtained membranes displayed an ion exchange capacity (IEC) close to 1.

Acidic Ionic Liquids Enabling Intermediate Temperature Operation Fuel Cells.

Herein we show that protic ionic liquids (PILs) are promising electrolytes for fuel cells operating in the temperature range 100-120 °C. ,-Diethyl--methyl-3-sulfopropan-1-ammonium hydrogen sulfate ([DEMSPA][HSA]), ,-diethyl--methyl-3-sulfopropan-1-ammonium triflate ([DEMSPA][TfO]), ,-diethyl-3-sulfopropan-1-ammonium hydrogen sulfate ([DESPA][HSA]), and ,-diethyl-3-sulfopropan-1-ammonium triflate ([DESPA][TfO]) are investigated in this study with regard to their specific conductivity, thermal stability, viscosity, and electrochemical properties. The [DEMSPA][TfO] and [DESPA][TfO] electrolytes offer high limiting current densities for the oxygen reduction reaction (ORR) on platinum electrodes, that is, about 1 order of magnitude larger than 98% HPO.

CO Oxidation on Planar Au/TiO Model Catalysts under Realistic Conditions: A Combined Kinetic and IR Study.

The oxidation of CO on planar Au/TiO model catalysts was investigated under pressure and temperature conditions similar to those for experiments with more realistic Au/TiO powder catalysts. The effects of a change of temperature, pressure, and gold coverage on the CO oxidation activity were studied. Additionally, the reasons for the deactivation of the catalysts were examined in long-term experiments.

Degradation Characteristics of Electrospun Gas Diffusion Layers with Custom Pore Structures for Polymer Electrolyte Membrane Fuel Cells.

Electrospinning has been demonstrated to be a versatile technique for producing hydrophobic gas diffusion layers (GDLs) with customized pore structures for the enhanced performance of polymer electrolyte membrane (PEM) fuel cells. However, the degradation characteristics of custom hydrophobic electrospun GDLs (eGDLs) have not yet been explored. Here, for the first time, we investigate the degradation characteristics of custom hydrophobic eGDLs via an ex situ accelerated degradation protocol using HO.

Model Studies on the Formation of the Solid Electrolyte Interphase: Reaction of Li with Ultrathin Adsorbed Ionic-Liquid Films and Co O (111) Thin Films.

In this work we aim towards the molecular understanding of the solid electrolyte interphase (SEI) formation at the electrode electrolyte interface (EEI). Herein, we investigated the interaction between the battery-relevant ionic liquid (IL) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMP-TFSI), Li and a Co O (111) thin film model anode grown on Ir(100) as a model study of the SEI formation in Li-ion batteries (LIBs). We employed mostly X-ray photoelectron spectroscopy (XPS) in combination with dispersion-corrected density functional theory calculations (DFT-D3).

Rapid Surface Modification of Ultrafiltration Membranes for Enhanced Antifouling Properties.

In this work, several ultrafiltration (UF) membranes with enhanced antifouling properties were fabricated using a rapid and green surface modification method that was based on the plasma-enhanced chemical vapor deposition (PECVD). Two types of hydrophilic monomers-acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) were, respectively, deposited on the surface of a commercial UF membrane and the effects of plasma deposition time (i.e.

Cathode-Electrolyte Interphase in a LiTFSI/Tetraglyme Electrolyte Promoting the Cyclability of VO.

VO, one of the earliest intercalation-type cathode materials investigated as a Li host, is characterized by an extremely high theoretical capacity (441 mAh g). However, the fast capacity fading upon cycling in conventional carbonate-based electrolytes is an unresolved issue. Herein, we show that using a LiTFSI/tetraglyme (1:1 in mole ratio) electrolyte yields a highly enhanced cycling ability of VO (from 20% capacity retention to 80% after 100 cycles at 50 mA g within 1.

Vacancy assisted diffusion on single-atom surface alloys.

Bimetallic surfaces can exhibit an improved catalytic activity through tailoring the concentration and/or the arrangement of the two metallic components. However, in order to be catalytically active, the active bimetallic surface structure has to be stable under operating conditions. Typically, structural changes in metals occur via vacancy diffusion.

Elucidating the Mechanism of Li Insertion into FeS/Carbon Synchrotron Studies.

The detailed understanding of kinetic and phase dynamics taking place in lithium-ion batteries (LIBs) is crucial for optimizing their properties. It was previously reported that FeS/C nanocomposites display a superior performance as anode materials in LIBs. However, the underlying lithium storage mechanism was not entirely understood during the 1st cycle.

Lithium containing layered high entropy oxide structures.

Layered Delafossite-type Li(MMMMM…M)O materials, a new class of high-entropy oxides, were synthesized by nebulized spray pyrolysis and subsequent high-temperature annealing. Various metal species (M = Ni, Co, Mn, Al, Fe, Zn, Cr, Ti, Zr, Cu) could be incorporated into this structure type, and in most cases, single-phase oxides were obtained. Delafossite structures are well known and the related materials are used in different fields of application, especially in electrochemical energy storage (e.

Tragacanth Gum as Green Binder for Sustainable Water-Processable Electrochemical Capacitor.

Enabling green fabrication processes for energy storage devices is becoming a key aspect in order to achieve a sustainable fabrication cycle. Here, the focus was on the exploitation of the tragacanth gum, an exudated gum like arabic and karaya gums, as green binder for the preparation of carbon-based materials for electrochemical capacitors. The electrochemical performance of tragacanth (TRGC)-based electrodes was thoroughly investigated and compared with another water-soluble binder largely used in this field, sodium-carboxymethyl cellulose (CMC).

Exploring the Reversibility of Phase Transformations in Aluminum Anodes through Operando Light Microscopy and Stress Analysis.

Aluminum is well-known to possess attractive properties for possible use as an anode material in Li-ion batteries (LIBs), but effort is still needed to understand how and why it degrades. Herein, investigations of the delithiation and the re-lithiation processes in Al thin films using an established operando light microscopic platform are pursued. Operando videos highlight that the extraction of Li from the β phase (LiAl) is accompanied by fracture and crack formation leading to the detachment of the α phase (Al) from the rest of the electrode.

Optimized Kinetics Match and Charge Balance Toward Potassium Ion Hybrid Capacitors with Ultrahigh Energy and Power Densities.

Potassium ion hybrid capacitors (PIHCs) are of particular interest benefiting from high energy/power densities. However, challenges lie in the kinetic mismatch between battery-type anode and capacitive-type cathode, as well as the difficulty in achieving optimized charge/mass balance. These significantly sacrifice the electrochemical performance of PIHCs.

Stabilization of Li-Rich Disordered Rocksalt Oxyfluoride Cathodes by Particle Surface Modification.

Promising theoretical capacities and high voltages are offered by Li-rich disordered rocksalt oxyfluoride materials as cathodes in lithium-ion batteries. However, as has been discovered for many other Li-rich materials, the oxyfluorides suffer from extensive surface degradation, leading to severe capacity fading. In the case of LiVOF, we have previously determined this to be a result of detrimental reactions between an unstable surface layer and the organic electrolyte.

Synthesis and Characterization of a Multication Doped Mn Spinel, LiNiCuFeMnO, as 5 V Positive Electrode Material.

The suitability of multication doping to stabilize the disordered 3̅ structure in a spinel is reported here. In this work, LiNiCuFeMnO was synthesized via a sol-gel route at a calcination temperature of 850 °C. LiNiCuFeMnO is evaluated as positive electrode material in a voltage range between 3.

Organic Liquid Crystals as Single-Ion Li Conductors.

The development of new materials for tomorrow's electrochemical energy storage technologies, based on thoroughly designed molecular architectures is at the forefront of materials research. In this line, we report herein the development of a new class of organic lithium-ion battery electrolytes, thermotropic liquid crystalline single-ion conductors, for which the single-ion charge transport is decoupled from the molecular dynamics (i. e.

Zn Metal Atom Doping on the Surface Plane of One-Dimesional NiMoO Nanorods with Improved Redox Chemistry.

The effect of zinc (Zn) doping and defect formation on the surface of nickel molybdate (NiMoO) structures with varying Zn content has been studied to produce one-dimensional electrodes and catalysts for electrochemical energy storage and ethanol oxidation, respectively. Zn-doped nickel molybdate (NiZnMoO, where = 0.1, 0.

pH Measurements Decipher H/Zn Intercalation Chemistry in High-Performance Aqueous Zn/δ-VO Batteries.

Vanadium oxides have been recognized to be among the most promising positive electrode materials for aqueous zinc metal batteries (AZMBs). However, their underlying intercalation mechanisms are still vigorously debated. To shed light on the intercalation mechanisms, high-performance δ-VO is investigated as a model compound.

Determination of the Volume Changes Occurring for Conversion/Alloying-Type Li-Ion Anodes upon Lithiation/Delithiation.

High-capacity lithium-ion anodes such as alloying-, conversion-, and conversion/alloying-type materials are subjected to extensive volume variation upon lithiation/delithiation. However, a careful examination of these processes at the particle and electrode level as well as the impact of the kind of lithium-ion uptake mechanism is still missing. Herein, we investigated the volume variation upon lithiation/delithiation for a series of conversion/alloying materials with a varying relative contribution of the alloying and conversion reaction, i.

Molecular Vanadium Oxides for Energy Conversion and Energy Storage: Current Trends and Emerging Opportunities.

Molecular vanadium oxides, or polyoxovanadates (POVs), have recently emerged as a new class of molecular energy conversion/storage materials, which combine diverse, chemically tunable redox behavior and reversible multielectron storage capabilities. This Review explores current challenges, major breakthroughs, and future opportunities in the use of POVs for energy conversion and storage. The reactivity, advantages, and limitations of POVs are explored, with a focus on their use in lithium and post-lithium-ion batteries, redox-flow batteries, and light-driven energy conversion.

Towards quantitative treatment of electron pair distribution function.

The pair distribution function (PDF) is a versatile tool to describe the structure of disordered and amorphous materials. Electron PDF (ePDF) uses the advantage of strong scattering of electrons, thus allowing small volumes to be probed and providing unique information on structure variations at the nano-scale. The spectrum of ePDF applications is rather broad: from ceramic to metallic glasses and mineralogical to organic samples.

Rechargeable Calcium-Sulfur Batteries Enabled by an Efficient Borate-Based Electrolyte.

Rechargeable metal-sulfur batteries show great promise for energy storage applications because of their potentially high energy and low cost. The multivalent-metal based electrochemical system exhibits the particular advantage of the feasibility of dendrite-free metal anode. Calcium (Ca) represents a promising anode material owing to the low reductive potential, high capacity, and abundant natural resources.

LiGeSBr-An Argyrodite Li-Ion Conductor Prepared by Mechanochemical Synthesis.

In recent years, the search for glassy and ceramic Li superionic conductors has received significant attention, mainly due to the renaissance of interest in all-solid-state batteries. Here, we report the mechanochemical synthesis of metastable LiGeSBr, which is, to the best of our knowledge, the first compound of the LiS-GeS-LiBr system. Applying combined synchrotron X-ray diffraction and neutron powder diffraction, we show LiGeSBr to crystallize in the 4̅3 space group and to be isostructural with argyrodite-type LiPSBr, but with a distinct difference in the S/Br site disorder (and improved anodic stability).