Browse
Submit Data
Databases
API
Help

Dataset Information

13 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Amorphous Redox-Rich Polysulfides for Mg Cathodes.

ABSTRACT: The lack of appropriate cathodes is restraining the advances of Mg batteries. Crystalline cathode materials suffer from sluggish reaction kinetics and low-capacity delivery. The finite type of crystalline structure further confines the rational design of cathode materials. Herein, we proposed amorphization and anion enrichment as a brand-new strategy to not only enhance the solid-state ion diffusion and provide more ion-storage sites in amorphous structure but also contribute to the local transfer of multiple electrons through the additional anionic redox centers. Accordingly, a series of amorphous titanium polysulfides (a-TiS _x , x = 2, 3, and 4) were designed, which significantly outperformed their crystalline counterparts and achieved a highly competitive energy density of ∼260 Wh/kg. The unique Mg²⁺ storage mechanism involves the dissociation/formation of S-S bonds and changes in the coordination number of Ti, namely, a mixture of conversion and intercalation reaction, accompanied by the joint cationic (Ti) and anionic (S) redox-rich chemistry. Our proposed amorphous and redox-rich design philosophy might provide an innovative direction for developing high-performance cathode materials for multivalent-ion batteries.

SUBMITTER: Mao M

PROVIDER: S-EPMC8397358 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Atomic-scale compositional mapping reveals Mg-rich amorphous calcium phosphate in human dental enamel.

Project description:Human dental enamel, the hardest tissue in the body, plays a vital role in protecting teeth from wear as a result of daily grinding and chewing as well as from chemical attack. It is well established that the mechanical strength and fatigue resistance of dental enamel are derived from its hierarchical structure, which consists of periodically arranged bundles of hydroxyapatite (HAP) nanowires. However, we do not yet have a full understanding of the in vivo HAP crystallization process that leads to this structure. Mg(2+) ions, which are present in many biological systems, regulate HAP crystallization by stabilizing its precursor, amorphous calcium phosphate (ACP), but their atomic-scale distribution within HAP is unknown. We use atom probe tomography to provide the first direct observations of an intergranular Mg-rich ACP phase between the HAP nanowires in mature human dental enamel. We also observe Mg-rich elongated precipitates and pockets of organic material among the HAP nanowires. These observations support the postclassical theory of amelogenesis (that is, enamel formation) and suggest that decay occurs via dissolution of the intergranular phase. This information is also useful for the development of more accurate models to describe the mechanical behavior of teeth.

| S-EPMC5014466 | biostudies-literature

Fundamental interplay between anionic/cationic redox governing the kinetics and thermodynamics of lithium-rich cathodes.

Project description:Reversible anionic redox has rejuvenated the search for high-capacity lithium-ion battery cathodes. Real-world success necessitates the holistic mastering of this electrochemistry's kinetics, thermodynamics, and stability. Here we prove oxygen redox reactivity in the archetypical lithium- and manganese-rich layered cathodes through bulk-sensitive synchrotron-based spectroscopies, and elucidate their complete anionic/cationic charge-compensation mechanism. Furthermore, via various electroanalytical methods, we answer how the anionic/cationic interplay governs application-wise important issues-namely sluggish kinetics, large hysteresis, and voltage fade-that afflict these promising cathodes despite widespread industrial and academic efforts. We find that cationic redox is kinetically fast and without hysteresis unlike sluggish anions, which furthermore show different oxidation vs. reduction potentials. Additionally, more time spent with fully oxidized oxygen promotes voltage fade. These fundamental insights about anionic redox are indispensable for improving lithium-rich cathodes. Moreover, our methodology provides guidelines for assessing the merits of existing and future anionic redox-based high-energy cathodes, which are being discovered rapidly.

| S-EPMC5738393 | biostudies-literature

Redox Mechanisms in Li and Mg Batteries Containing Poly(phenanthrene quinone)/Graphene Cathodes using Operando ATR-IR Spectroscopy.

Project description:The redox reaction mechanism of a poly(phenanthrene quinone)/graphene composite (PFQ/rGO) was investigated using operando attenuated total reflection infrared (ATR-IR) spectroscopy during cycling of Li and Mg batteries. The reference phenanthrene quinone and the Li and Mg salts of the hydroquinone monomers were synthesized and their IR spectra were measured. Additionally, IR spectra were calculated using DFT. A comparison of all three spectra allowed us to accurately assign the C=O and C-O- vibration bands and confirm the redox mechanism of the quinone/Li salt of hydroquinone, with radical anion formation as the intermediate product. PFQ/rGO also showed exceptional performance in an Mg battery: A potential of 1.8?V versus Mg/Mg2+ , maximum capacity of 186?mAh?g-1 (335?Wh?kg-1 of cathode material), and high capacity retention with only 8?% drop/100?cycles. Operando ATR-IR spectroscopy was performed in a Mg/organic system, revealing an analogous redox mechanism to a Li/organic cell.

| S-EPMC7317575 | biostudies-literature

Covalency does not suppress O<sub>2</sub> formation in 4d and 5d Li-rich O-redox cathodes.

Project description:Layered Li-rich transition metal oxides undergo O-redox, involving the oxidation of the O2- ions charge compensated by extraction of Li+ ions. Recent results have shown that for 3d transition metal oxides the oxidized O2- forms molecular O2 trapped in the bulk particles. Other forms of oxidised O2- such as O22- or (O-O)n- with long bonds have been proposed, based especially on work on 4 and 5d transition metal oxides, where TM-O bonding is more covalent. Here, we show, using high resolution RIXS that molecular O2 is formed in the bulk particles on O2‒ oxidation in the archetypal Li-rich ruthenates and iridate compounds, Li2RuO3, Li2Ru0.5Sn0.5O3 and Li2Ir0.5Sn0.5O3. The results indicate that O-redox occurs across 3, 4, and 5d transition metal oxides, forming O2, i.e. the greater covalency of the 4d and 5d compounds still favours O2. RIXS and XAS data for Li2IrO3 are consistent with a charge compensation mechanism associated primarily with Ir redox up to and beyond the 5+ oxidation state, with no evidence of O-O dimerization.

| S-EPMC8137948 | biostudies-literature

Redox Chemistry and the Role of Trapped Molecular O<sub>2</sub> in Li-Rich Disordered Rocksalt Oxyfluoride Cathodes.

Project description:In the search for high energy density cathodes for next-generation lithium-ion batteries, the disordered rocksalt oxyfluorides are receiving significant attention due to their high capacity and lower voltage hysteresis compared with ordered Li-rich layered compounds. However, a deep understanding of these phenomena and their redox chemistry remains incomplete. Using the archetypal oxyfluoride, Li2MnO2F, we show that the oxygen redox process in such materials involves the formation of molecular O2 trapped in the bulk structure of the charged cathode, which is reduced on discharge. The molecular O2 is trapped rigidly within vacancy clusters and exhibits minimal mobility unlike free gaseous O2, making it more characteristic of a solid-like environment. The Mn redox process occurs between octahedral Mn3+ and Mn4+ with no evidence of tetrahedral Mn5+ or Mn7+. We furthermore derive the relationship between local coordination environment and redox potential; this gives rise to the observed overlap in Mn and O redox couples and reveals that the onset potential of oxide ion oxidation is determined by the degree of ionicity around oxygen, which extends models based on linear Li-O-Li configurations. This study advances our fundamental understanding of redox mechanisms in disordered rocksalt oxyfluorides, highlighting their promise as high capacity cathodes.

| S-EPMC7872422 | biostudies-literature

Highly efficient conversion of surplus electricity to hydrogen energy via polysulfides redox.

Project description:Decoupled electrolysis of water is a promising strategy for peak load regulation of electricity. The key to developing this technology is to construct decoupled devices containing stable redox mediators and corresponding efficient catalysts, which remains a considerable challenge. Herein, we designed a high-performance device, using polysulfides as mediators and graphene-encapsulated CoNi as catalysts. It produced H2 with a low potential of 0.82 V at 100 mA/cm2, saving 60.2% more energy than direct water electrolysis. The capacity of H2 production reached 2.5×105 mAh/cm2, which is the highest capacity reported so far. This device exhibited excellent cyclability in 15-day recycle tests, without any decay of performance. The calculation results revealed that the electronic structure of the graphene shell was modulated by the electron transfer from N-dopant and metal core, which significantly facilitated recycle of polysulfides on graphene surfaces. This study provides a promising method for constructing a smart grid by developing efficient decoupled devices.

| S-EPMC8454573 | biostudies-literature

Chemisorption of polysulfides through redox reactions with organic molecules for lithium-sulfur batteries.

Project description:Lithium-sulfur battery possesses high energy density but suffers from severe capacity fading due to the dissolution of lithium polysulfides. Novel design and mechanisms to encapsulate lithium polysulfides are greatly desired by high-performance lithium-sulfur batteries towards practical applications. Herein, we report a strategy of utilizing anthraquinone, a natural abundant organic molecule, to suppress dissolution and diffusion of polysulfides species through redox reactions during cycling. The keto groups of anthraquinone play a critical role in forming strong Lewis acid-based chemical bonding. This mechanism leads to a long cycling stability of sulfur-based electrodes. With a high sulfur content of ~73%, a low capacity decay of 0.019% per cycle for 300 cycles and retention of 81.7% over 500 cycles at 0.5?C rate can be achieved. This finding and understanding paves an alternative avenue for the future design of sulfur-based cathodes toward the practical application of lithium-sulfur batteries.

| S-EPMC5816018 | biostudies-literature

Amorphous Vanadium Oxide Thin Films as Stable Performing Cathodes of Lithium and Sodium-Ion Batteries.

Project description:Herein, we report additive- and binder-free pristine amorphous vanadium oxide (a-VOx) for Li- and Na-ion battery application. Thin films of a-VOx with a thickness of about 650 nm are grown onto stainless steel substrate from crystalline V2O5 target using pulsed laser deposition (PLD) technique. Under varying oxygen partial pressure (pO2) environment of 0, 6, 13 and 30 Pa, films bear O/V atomic ratios 0.76, 2.13, 2.25 and 2.0, respectively. The films deposited at 6‑30 Pa have a more atomic percentage of V5+ than that of V4+ with a tendency of later state increased as pO2 rises. Amorphous VOx films obtained at moderate pO2 levels are found superior to other counterparts for cathode application in Li- and Na-ion batteries with reversible capacities as high as 300 and 164 mAh g-1 at 0.1 C current rate, respectively. At the end of the 100th cycle, 90% capacity retention is noticed in both cases. The observed cycling trend suggests that more is the (V5+) stoichiometric nature of a-VOx better is the electrochemistry.

| S-EPMC6235769 | biostudies-literature

Rendering Redox Reactions of Cathodes in Li-Ion Capacitors Enabled by Lanthanides.

Project description:Capacitors allow extremely fast charge and discharge operations, which is a challenge faced by recent metal-ion batteries despite having highly improved energy densities. Thus, combined type electric energy storage devices that can integrate high energy density and high power density with high potentials, can overcome the shortcomings of the current metal-ion batteries and capacitors. However, the limited capacities of cathode materials owing to the barren redox reactions are regarded as an obstacle for the development of future high-performance hybrid metal-ion capacitors. In this study, we demonstrate the redox-reaction-rendering effect of the much overlooked lanthanide elements when used as the cathode of lithium-ion capacitors using the mesoporous carbon (MC) as a matrix material. Consequently, these lanthanide elements can effectively enrich the redox reaction, thus improving the capacity of the matrix materials by more than two times. Typically, the Gd-elemental decoration of MC surprisingly enhances the capacity by almost two times as compared with the underacted MC. Furthermore, the La nanoparticles (NPs) decoration depicts the same behavior. Evident redox peaks were formed on the original rectangular cyclic voltammetry (CV) curves. This study provides the first example of embedding lanthanide elements on matrix materials to enrich the desired redox reactions for improving the electrochemical performances.

| S-EPMC6990622 | biostudies-literature

Surface Chemistry Dependence on Aluminum Doping in Ni-rich LiNi0.8Co0.2-yAlyO2 Cathodes.

Project description:Aluminum is a common dopant across oxide cathodes for improving the bulk and cathode-electrolyte interface (CEI) stability. Aluminum in the bulk is known to enhance structural and thermal stability, yet the exact influence of aluminum at the CEI remains unclear. To address this, we utilized a combination of X-ray photoelectron and absorption spectroscopy to identify aluminum surface environments and extent of transition metal reduction for Ni-rich LiNi0.8Co0.2-yAlyO2 (0%, 5%, or 20% Al) layered oxide cathodes tested at 4.75 V under thermal stress (60?°C). For these tests, we compared the conventional LiPF6 salt with the more thermally stable LiBF4 salt. The CEI layers are inherently different between these two electrolyte salts, particularly for the highest level of Al-doping (20%) where a thicker (thinner) CEI layer is found for LiPF6 (LiBF4). Focusing on the aluminum environment, we reveal the type of surface aluminum species are dependent on the electrolyte salt, as Al-O-F- and Al-F-like species form when using LiPF6 and LiBF4, respectively. In both cases, we find cathode-electrolyte reactions drive the formation of a protective Al-F-like barrier at the CEI in Al-doped oxide cathodes.

| S-EPMC6881288 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data