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Journal ArticleDOI

Reversible anionic redox chemistry in high-capacity layered-oxide electrodes

TLDR
In this article, the reactivity of a class of high-capacity oxides with a single redox cation has been investigated and it has been shown that these oxides exhibit sustainable reversible capacities as high as 230 mAh/g−1 and good cycling behavior with no signs of voltage decay.
Abstract
Li-ion batteries have contributed to the commercial success of portable electronics and may soon dominate the electric transportation market provided that major scientific advances including new materials and concepts are developed. Classical positive electrodes for Li-ion technology operate mainly through an insertion-deinsertion redox process involving cationic species. However, this mechanism is insufficient to account for the high capacities exhibited by the new generation of Li-rich (Li1+xNiyCozMn(1−x−y−z)O2) layered oxides that present unusual Li reactivity. In an attempt to overcome both the inherent composition and the structural complexity of this class of oxides, we have designed structurally related Li2Ru1−ySnyO3 materials that have a single redox cation and exhibit sustainable reversible capacities as high as 230 mA h g−1. Moreover, they present good cycling behaviour with no signs of voltage decay and a small irreversible capacity. We also unambiguously show, on the basis of an arsenal of characterization techniques, that the reactivity of these high-capacity materials towards Li entails cumulative cationic (Mn+→M(n+1)+) and anionic (O2−→O22−) reversible redox processes, owing to the d-sp hybridization associated with a reductive coupling mechanism. Because Li2MO3 is a large family of compounds, this study opens the door to the exploration of a vast number of high-capacity materials.

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Journal ArticleDOI

Disordered Li-rich, Ti-based oxyfluoride cathode with multiple cation and anion redox chemistry

TL;DR: Li et al. as mentioned in this paper proposed a promising set of high energy density DRX materials with composition of inexpensive, eco-friendly and earth abundant elements with high discharge capacities of 285.3 mAh g−1 and energy content of 909.5 Wh kg−1.
Journal ArticleDOI

The role of covalent bonding and anionic redox for the performance of sodium cobaltate electrode materials

TL;DR: In this article, thin films of sodium cobaltate demonstrate a mixed redox behavior with strong oxygen participation well within the reversible intercalation range, attributed to an increasing degree of covalency of the transition metal-oxygen (TM-O) bonds during deintercalation in combination with a high structural flexibility of the material.
Journal ArticleDOI

Magnetic and electrical anisotropy with correlation and orbital effects in dimerized honeycomb ruthenate L i 2 Ru O 3

TL;DR: In this article, the anisotropy of resistivity and magnetic susceptibility was investigated using high-quality single crystals, and it was concluded that this anisotropic behavior is due to the correlation effects combined with the unique orbital structure and the dimerization of Ru $4d$ bands.
Journal ArticleDOI

Phosphorus anionic redox activity revealed by operando P K-edge X-ray absorption spectroscopy on diphosphonate-based conversion materials in Li-ion batteries

TL;DR: Using operando X-ray absorption spectroscopy at the P K-edge experiment, an additional contribution of reversible ligand co-cycling based on the P-atoms of the diphosphonate ligands is demonstrated, upon delithiation occurring during the first potential plateau, which matches perfectly to previous investigations using Fe K- edge XAS.
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Suppress Oxygen Evolution of Lithium-Rich Manganese- Based Cathode Materials via an Integrated Strategy

TL;DR: LiYO2 nanocoating has the function of structural constraint and protection, that protecting the lattice oxygen exposed to the surface, thus avoiding irreversible oxidation as discussed by the authors , which can provide a fast Li + transfer channel, which enables the sample to have excellent rate performance.
References
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Journal ArticleDOI

Generalized Gradient Approximation Made Simple

TL;DR: A simple derivation of a simple GGA is presented, in which all parameters (other than those in LSD) are fundamental constants, and only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked.
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Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set.

TL;DR: An efficient scheme for calculating the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set is presented and the application of Pulay's DIIS method to the iterative diagonalization of large matrices will be discussed.
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Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides

TL;DR: The effective ionic radii of Shannon & Prewitt [Acta Cryst. (1969), B25, 925-945] are revised to include more unusual oxidation states and coordinations as mentioned in this paper.
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Issues and challenges facing rechargeable lithium batteries

TL;DR: A brief historical review of the development of lithium-based rechargeable batteries is presented, ongoing research strategies are highlighted, and the challenges that remain regarding the synthesis, characterization, electrochemical performance and safety of these systems are discussed.
Journal ArticleDOI

Building better batteries

TL;DR: Researchers must find a sustainable way of providing the power their modern lifestyles demand to ensure the continued existence of clean energy sources.
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