Accessing Mg-Ion Storage in VPS via Combined Cationic-Anionic Redox with Selective Bond Cleavage.

Magnesium batteries attract interest as alternative energy-storage devices because of elemental abundance and potential for high energy density. Development is limited by the absence of suitable cathodes, associated with poor diffusion kinetics resulting from strong interactions between Mg and the host structure. VPS is reported as a positive electrode material for rechargeable magnesium batteries.

Superionic lithium transport via multiple coordination environments defined by two-anion packing.

Fast cation transport in solids underpins energy storage. Materials design has focused on structures that can define transport pathways with minimal cation coordination change, restricting attention to a small part of chemical space. Motivated by the greater structural diversity of binary intermetallics than that of the metallic elements, we used two anions to build a pathway for three-dimensional superionic lithium ion conductivity that exploits multiple cation coordination environments.

Simultaneous Surface-Enhanced Raman Scattering with a Kerr Gate for Fluorescence Suppression.

The combination of surface-enhanced and Kerr-gated Raman spectroscopy for the enhancement of the Raman signal and suppression of fluorescence is reported. Surface-enhanced Raman scattering (SERS)-active gold substrates were demonstrated for the expansion of the surface generality of optical Kerr-gated Raman spectroscopy, broadening its applicability to the study of analytes that show a weak Raman signal in highly fluorescent media under (pre)resonant conditions. This approach is highlighted by the well-defined spectra of rhodamine 6G, Nile red, and Nile blue.

Concluding remarks: a summary of the on rechargeable non-aqueous metal-oxygen batteries.

The on rechargeable non-aqueous metal-oxygen batteries is summarised. The remarks paper highlights the specific science contributions made in the vital areas of oxygen reduction and evolution reaction mechanisms in non-aqueous electrolytes; material developments for stable metal-oxygen battery cathodes; achieving stable metal anodes and protected interfaces; and, finally, contributions concerning the progress towards practical metal-oxygen batteries. Key conclusions associated with these papers will be highlighted in an order such that readers can identify papers that they would like to explore in more detail.

Effect of alkali-metal cation on oxygen adsorption at Pt single-crystal electrodes in non-aqueous electrolytes.

The effect of Group 1 alkali-metal cations (Na, K, and Cs) on the oxygen reduction and evolution reactions (ORR and OER) using dimethyl sulfoxide (DMSO)-based electrolytes was investigated. Cyclic voltammetry (CV) utilising different Pt-electrode surfaces (polycrystalline Pt, Pt(111) and Pt(100)) was undertaken to investigate the influence of surface structure upon the ORR and OER. For K and Cs, negligible variation in the CV response (in contrast to Na) was observed using Pt(111), Pt(100) and Pt(poly) electrodes, consistent with a weak surface-metal/superoxide complex interaction.

Localised degradation within sulfide-based all-solid-state electrodes visualised by Raman mapping.

The distribution of degradation products, before and after cycling, within common sulfide-based solid electrolytes (β-LiPS, LiPSCl and LiGePS) was mapped using Raman microscopy. All composite electrodes displayed the appearance of side reaction products after the initial charge-discharge cycle, located at the site of a LiNiMnCoO particle.

Nanophase-photocatalysis: loading, storing, and release of HO using graphitic carbon nitride.

A blue light mediated photochemical process using solid graphitic carbon nitride (g-CN) in ambient air/isopropanol vapour is suggested to be linked to "nanophase" water inclusions and is shown to produce approx. 50 μmol HO per gram of g-CN, which can be stored in the solid g-CN for later release for applications, for example, in disinfection or anti-bacterial surfaces.

Towards commercialization of fluorinated cation-disordered rock-salt Li-ion cathodes.

Cation-disordered rock-salt cathodes (DRX) are promising materials that could deliver high capacities (>250 mAh g) with Earth abundant elements and materials. However, their electrochemical performances, other than the capacity, should be improved to be competitive cathodes, and many strategies have been introduced to enhance DRXs. Fluorination has been shown to inhibit oxygen loss and increase power density.

Band Alignments, Electronic Structure, and Core-Level Spectra of Bulk Molybdenum Dichalcogenides (MoS, MoSe, and MoTe).

A comprehensive study of bulk molybdenum dichalcogenides is presented with the use of soft and hard X-ray photoelectron (SXPS and HAXPES) spectroscopy combined with hybrid density functional theory (DFT). The main core levels of MoS, MoSe, and MoTe are explored. Laboratory-based X-ray photoelectron spectroscopy (XPS) is used to determine the ionization potential (IP) values of the MoX series as 5.

Lithium Insertion into Graphitic Carbon Observed via Operando Kerr-Gated Raman Spectroscopy Enables High State of Charge Diagnostics.

Monitoring the precise lithium inventory of the graphitic carbon electrode within the Li-ion battery, in order to assess cell aging, has remained challenging. Herein, operando electrochemical Kerr-gated Raman spectroscopy measurements on microcrystalline graphite during complete lithium insertion and extraction are reported and compared to conventional continuous-wave Raman microscopy. Suppression of the fluorescence emission signals via use of the Kerr gate enabled the measurement of the Raman graphitic bands of highly lithiated graphite where 0.

Long-Life and pH-Stable SnO-Coated Au Nanoparticles for SHINERS.

Shell-isolated nanoparticles (SHINs) with a 37 nm gold core and an 11 nm tin dioxide (SnO) coating exhibited long-life Raman enhancement for 3 months and a wide pH stability of pH 2-13 in comparison with conventional SiO-coated SHINs. Herein, Au-SnO is demonstrated as a more durable SHIN for use in the technique Shell-Isolated Nanoparticles for Enhanced Raman Spectroscopy (SHINERS).

Dynamics of Solid-Electrolyte Interphase Formation on Silicon Electrodes Revealed by Combinatorial Electrochemical Screening.

Revealing how formation protocols influence the properties of the solid-electrolyte interphase (SEI) on Si electrodes is key to developing the next generation of Li-ion batteries. SEI understanding is, however, limited by the low-throughput nature of conventional characterisation techniques. Herein, correlative scanning electrochemical cell microscopy (SECCM) and shell-isolated nanoparticles for enhanced Raman spectroscopy (SHINERS) are used for combinatorial screening of the SEI formation under a broad experimental space (20 sets of different conditions with several repeats).

A Pyrene-4,5,9,10-Tetraone-Based Covalent Organic Framework Delivers High Specific Capacity as a Li-Ion Positive Electrode.

Electrochemically active covalent organic frameworks (COFs) are promising electrode materials for Li-ion batteries. However, improving the specific capacities of COF-based electrodes requires materials with increased conductivity and a higher concentration of redox-active groups. Here, we designed a series of pyrene-4,5,9,10-tetraone COF (PT-COF) and carbon nanotube (CNT) composites (denoted as PT-COFX, where = 10, 30, and 50 wt % of CNT) to address these challenges.

Investigating the presence of adsorbed species on Pt steps at low potentials.

The study of the OH adsorption process on Pt single crystals is of paramount importance since this adsorbed species is considered the main intermediate in many electrochemical reactions of interest, in particular, those oxidation reactions that require a source of oxygen. So far, it is frequently assumed that the OH adsorption on Pt only takes place at potentials higher than 0.55 V (versus the reversible hydrogen electrode), regardless of the Pt surface structure.

Ordered Oxygen Vacancies in the Lithium-Rich Oxide LiCuSbO, a Triclinic Structure Type Derived from the Cubic Rocksalt Structure.

Li-rich rocksalt oxides are promising candidates as high-energy density cathode materials for next-generation Li-ion batteries because they present extremely diverse structures and compositions. Most reported materials in this family contain as many cations as anions, a characteristic of the ideal cubic closed-packed rocksalt composition. In this work, a new rocksalt-derived structure type is stabilized by selecting divalent Cu and pentavalent Sb cations to favor the formation of oxygen vacancies during synthesis.

Extended Condensed Ultraphosphate Frameworks with Monovalent Ions Combine Lithium Mobility with High Computed Electrochemical Stability.

Extended anionic frameworks based on condensation of polyhedral main group non-metal anions offer a wide range of structure types. Despite the widespread chemistry and earth abundance of phosphates and silicates, there are no reports of extended ultraphosphate anions with lithium. We describe the lithium ultraphosphates LiPO and LiPO based on extended layers and chains of phosphate, respectively.

Element selection for crystalline inorganic solid discovery guided by unsupervised machine learning of experimentally explored chemistry.

The selection of the elements to combine delimits the possible outcomes of synthetic chemistry because it determines the range of compositions and structures, and thus properties, that can arise. For example, in the solid state, the elemental components of a phase field will determine the likelihood of finding a new crystalline material. Researchers make these choices based on their understanding of chemical structure and bonding.

Trapped interfacial redox introduces reversibility in the oxygen reduction reaction in a non-aqueous Ca electrolyte.

Electrochemical investigations of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) have been conducted in a Ca-containing dimethyl sulfoxide electrolyte. While the ORR appears irreversible, the introduction of a tetrabutylammonium perchlorate (TBAClO) co-salt in excess concentrations results in the gradual appearance of a quasi-reversible OER process. Combining the results of systematic cyclic voltammetry investigations, the degree of reversibility depends on the ion pair competition between Ca and TBA cations to interact with generated superoxide (O ).

The Effect of Degrees of Inversion on the Electronic Structure of Spinel NiCoO: A Density Functional Theory Study.

In this study, electronic structure calculations and Bader charge analysis have been completed on the inverse, intermediate, and normal spinel structures of NiCoO in both primitive and conventional cells, using density functional theory with Hubbard correction. Three spinel structures have been computed in the primitive cell, where the fully inverse spinel, 50% intermediate spinel, and normal spinel can be acquired by swapping Ni and Co atoms on tetrahedral and octahedral sites. Furthermore, NiCoO with different degrees of inversion in the conventional cells was also investigated, along with their doping energies.

Crosslinked Polyimide and Reduced Graphene Oxide Composites as Long Cycle Life Positive Electrode for Lithium-Ion Cells.

Conjugated polymers with electrochemically active redox groups are a promising class of positive electrode material for lithium-ion batteries. However, most polymers, such as polyimides, possess low intrinsic conductivity, which results in low utilization of redox-active sites during charge cycling and, consequently, poor electrochemical performance. Here, it was shown that this limitation can be overcome by synthesizing polyimide composites (PIX) with reduced graphene oxide (rGO) using an in situ polycondensation reaction.