Li5VF4(SO4)2: A Prototype High-Voltage Li-Ion Cathode

Vincent, Rebecca C.; Vishnoi, Pratap; Preefer, Molleigh B.; Shen, Julie; Seeler, Fabian; Persson, Kristin A.; Seshadri, Ram

doi:10.1021/acsami.0c14781

Cited by 4 publications

(1 citation statement)

References 59 publications

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“…In Figure 2 and Figures S7 and S8, Supporting Information, a scatter plot with a gradient of different colors denoting the capacitive tendency is used to position the 50 different materials. [ 5,50–96 ] Each of these materials is accompanied by voltammograms which were extracted from scientific publications. They were selected due to the fact that they are the most frequently applied materials in batteries and pseudocapacitors.…”

Section: Resultsmentioning

confidence: 99%

Electron Delocalization and Electrochemical Potential Distribution Phenomena in Faradaic Electrode Materials for Understanding Electrochemical Behavior

Zhu,

Deebansok,

Deng

et al. 2024

Advanced Energy Materials

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Electrochemical energy storage devices are built upon the foudations of batteries and supercapacitors. In the past decade, new pseudocapacitor‐like electrodes are intensively developed to obtain superior energy storage performance. Pseudocapacitive matarials store charge through Faradaic processes, while the electrochemical signal remains like electrochemical double‐layer capacitors (EDLCs). To address this controversy, an analytical model is introduced for evaluating the voltammograms of electrode materials. Given this, the work focuses on understanding the origin of the pseudocapacitive phenomena in the cyclic voltammetry (CV) electrochemical signal. Based on electron transfer mechanism and tunnelling effect within the atomic structure, pseudocapacitive matarials possess a high electron delocalization possibility related to the redox centers number and initiates the electrochemical potential distribution among neighboring redox sites, which is consequently observed in the electrochemical signal as the plateau feature in CV, like EDLC. First, the determination of the capacitive tendency of various electrode materials is proposed, which turns out to be relative to the redox centers number (n) and total charge (Z). Here, when this number is large, electron hopping will very likely happen. The developed model is versatile to predict rate/potential regimes for the maximum faradaic storage, and then well differentiates the pseudocapacitive and battery materials.

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Section: Resultsmentioning

confidence: 99%

Electron Delocalization and Electrochemical Potential Distribution Phenomena in Faradaic Electrode Materials for Understanding Electrochemical Behavior

Zhu,

Deebansok,

Deng

et al. 2024

Advanced Energy Materials

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The Development and Prospect of Stable Polyanion Compound Cathodes in LIBs and Promising Complementers

Guo,

Chu,

Zhang

et al. 2024

Small Methods

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Cathode materials are usually the key to determining battery capacity, suitable cathode materials are an important prerequisite to meet the needs of large‐scale energy storage systems in the future. Polyanionic compounds have significant advantages in metal ion storage, such as high operating voltage, excellent structural stability, safety, low cost, and environmental friendliness, and can be excellent cathode options for rechargeable metal‐ion batteries. Although some polyanionic compounds have been commercialized, there are still some shortcomings in electronic conductivity, reversible specific capacity, and rate performance, which obviously limits the development of polyanionic compound cathodes in large‐scale energy storage systems. Up to now, many strategies including structural design, ion doping, surface coating, and electrolyte optimization have been explored to improve the above defects. Based on the above contents, this paper briefly reviews the research progress and optimization strategies of typical polyanionic compound cathodes in the fields of lithium‐ion batteries (LIBs) and other promising metal ion batteries (sodium ion batteries (SIBs), potassium ion batteries (PIBs), magnesium ion batteries (MIBs), calcium ion batteries (CIBs), zinc ion batteries (ZIBs), aluminum ion batteries (AIBs), etc.), aiming to provide a valuable reference for accelerating the commercial application of polyanionic compound cathodes in rechargeable battery systems.

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Lithium Vanadium Polyanionic Composite Multielectron Intercalation Cathode Derived from Thermodynamically Unstable Li₂VP₂O₇/Li₂VP₂O₇F

Lokeswararao

Viji

Budumuru

et al. 2022

ACS Appl. Energy Mater.

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LiVP 2 O 7 is a well-explored cathode that supports reversible single electron extraction with a theoretical capacity of 115 mA h g −1 . Hypothetical Li 2 VP 2 O 7 F or Li 2 VP 2 O 7 compounds, with an additional Li and F in the structure or Li with vanadium in the lower oxidation state V 2+ , are expected to exchange two moles of lithium from the cathode. Li 2 VP 2 O 7 F synthesis is attempted through a sol−gel process to explore the possibility of such multielectron cathode material. Several syntheses with final annealing at 800 °C in the Ar or N 2 /H 2 (95:5) resulted in compounds exhibiting identical X-ray diffraction (XRD) patterns. However, none of these compositions has any significant fluorine content in them. Surprisingly, sol−gel synthesis of the nominal composition, i.e., Li 2 VP 2 O 7 , without any F addition in the initial precursor also resulted in a similar XRD pattern. These XRD patterns are comparable to the ones reported in the literature for Li 2 VP 2 O 7 composition. Interestingly, we find that neither the Li 2 VP 2 O 7 F nor Li 2 VP 2 O 7 compound is thermodynamically stable. Rather, it forms roughly an equimolar structural mixture of three different phases, viz., Li 9 V 3 (P 2 O 7 ) 3 (PO 4 ) 2 , Li 3 V 2 (PO 4 ) 3 , and LiVP 2 O 7 , as discerned from the detailed structural studies performed using X-ray diffraction, Rietveld refinement, and chemical composition analysis performed using proton-induced γ-ray emission and proton elastic backscattering spectrometry. The electrochemical studies, interestingly, exhibit two reversible redox processes with nearly flat potential and an average voltage of 3.86 and 1.72 V. A very high first cycle capacity of ∼340 mA h g −1 is reported for the first time. The capacity related to second Li fades upon cycling, providing a net capacity of ∼200 mA h g −1 . The nominal composition of Li 2 VP 2 O 7 F synthesized in N 2 /H 2 (95:5) gas flow exhibited the best electrochemical properties for a single lithium intercalation reaction. KEYWORDS: lithium-ion battery, Li 2 VP 2 O 7 F and Li 2 VP 2 O 7 cathodes, sol−gel method, multielectron intercalation, electrochemical properties

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Li₅VF₄(SO₄)₂: A Prototype High-Voltage Li-Ion Cathode

Cited by 4 publications

References 59 publications

Electron Delocalization and Electrochemical Potential Distribution Phenomena in Faradaic Electrode Materials for Understanding Electrochemical Behavior

Electron Delocalization and Electrochemical Potential Distribution Phenomena in Faradaic Electrode Materials for Understanding Electrochemical Behavior

The Development and Prospect of Stable Polyanion Compound Cathodes in LIBs and Promising Complementers

Lithium Vanadium Polyanionic Composite Multielectron Intercalation Cathode Derived from Thermodynamically Unstable Li₂VP₂O₇/Li₂VP₂O₇F

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Li5VF4(SO4)2: A Prototype High-Voltage Li-Ion Cathode

Cited by 4 publications

References 59 publications

Electron Delocalization and Electrochemical Potential Distribution Phenomena in Faradaic Electrode Materials for Understanding Electrochemical Behavior

Electron Delocalization and Electrochemical Potential Distribution Phenomena in Faradaic Electrode Materials for Understanding Electrochemical Behavior

The Development and Prospect of Stable Polyanion Compound Cathodes in LIBs and Promising Complementers

Lithium Vanadium Polyanionic Composite Multielectron Intercalation Cathode Derived from Thermodynamically Unstable Li2VP2O7/Li2VP2O7F

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Product

Resources

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Li₅VF₄(SO₄)₂: A Prototype High-Voltage Li-Ion Cathode

Lithium Vanadium Polyanionic Composite Multielectron Intercalation Cathode Derived from Thermodynamically Unstable Li₂VP₂O₇/Li₂VP₂O₇F