Negligible Voltage Hysteresis with Strong Anionic Redox in Conventional Battery Electrode

<div>Lattice oxygen redox reactions (ORR) offers opportunities for developing highcapacity batteries, however, suffers the notoriously high voltage hysteresis and low initial coulombic efficiency, which hinder its practical applications. Particularly, ORR was widely considered inherent to these kinetic issues. In this paper, unambiguous evidence of strong and reversible ORR is found in Na2/3Ni1/3Mn2/3O2, which displays negligible voltage hysteresis (0.1 V) and high initial coulombic efficiency with a highly stable electrochemical profile. Our independent and quantitative analysis of all the Ni, Mn and O states consistently interpret the redox mechanism of Na2/3Ni1/3Mn2/3O2, which reveals, for the first time, a conventional 3d transition-metal ORR system with facile kinetics and highly stable electrochemical profile that previously found only in cationic redox systems.</div>

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Unfolding the Hidden Message of Anode-Free Lithium Metal Battery

10.21203/rs.3.rs-45279/v1 ◽

2020 ◽

Author(s):

Chen-Jui Huang ◽

Balamurugan Thirumalraj ◽

Hsien-Chu Tao ◽

Kassie Nigus Shitaw ◽

Tesfaye Teka Hagos ◽

...

Keyword(s):

Coulombic Efficiency ◽

Rate Capability ◽

Reversible Capacity ◽

Data Interpretation ◽

Lithium Metal ◽

Practical Applications ◽

Lithium Metal Batteries ◽

Cathode Degradation ◽

Other Information ◽

First Time

Abstract Lithium metal batteries (LMBs) have been revisited and gained great attention due to significantly mitigated formation of Li dendrite in the past decade. Recently, anode-free lithium metal batteries (AFLMBs) are proposed and have been studied intensively to potentially outperform LMBs due to higher energy density and reduced safety hazards since the absence of Li metal during the fabrication process of the cell. In general, researchers compare capacity retention, reversible capacity, or rate capability of the cells to study the electrochemical performance of batteries. However, evaluating the behavior of batteries from limited aspects would easily overlook other information hidden deep inside the meretricious results or even lead to misguided data interpretation. In this work, an integrated protocol combining different types of cell configuration is proposed and validated for the first time to unravel the concealed messages in LMBs and AFLMBs. Irreversible coulombic efficiency (irr-CE) from various contributions including reductive electrolyte decomposition, dead Li formation, 1st intrinsic irreversible capacity of a cathode, and the subsequent irreversible reactions at cathode containing oxidative electrolyte decomposition and cathode degradation upon cycling are successfully determined separately by the integrated protocol for the first time. The decrypted information obtained from the proposed protocol provides an insightful understanding of behaviors of LMBs and AFLMBs, which promotes their development for practical applications.

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Superionic Lithium Intercalation through 2 nm x 2 nm Columns in the Crystallographic Shear Phase Nb18W8O69

10.26434/chemrxiv.11231153.v1 ◽

2019 ◽

Author(s):

Kent Griffith ◽

Clare Grey

Keyword(s):

High Performance ◽

Rate Capability ◽

Block Size ◽

Lithium Intercalation ◽

Resonance Spectroscopy ◽

Complex Metal Oxides ◽

Battery Electrode ◽

Crystallographic Shear ◽

Battery Material ◽

First Time

Nb18W8O69 (9Nb2O5×8WO3) is the tungsten-rich end-member of the Wadsley–Roth crystallographic shear (cs) structures within the Nb2O5–WO3 series. It has the largest block size of any known, stable Wadsley–Roth phase, comprising 5 ´ 5 units of corner-shared MO6 octahedra between the shear planes, giving rise to 2 nm ´ 2 nm blocks. Rapid lithium intercalation is observed in this new candidate battery material and 7Li pulsed field gradient nuclear magnetic resonance spectroscopy – measured in a battery electrode for the first time at room temperature – reveals superionic lithium conductivity. In addition to its promising rate capability, Nb18W8O69 adds a piece to the larger picture of our understanding of high-performance Wadsley–Roth complex metal oxides.

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Boost sodium-ion batteries to commercialization: Strategies to enhance initial Coulombic efficiency of hard carbon anode

Nano Energy ◽

10.1016/j.nanoen.2020.105738 ◽

2020 ◽

pp. 105738

Author(s):

Minghao Zhang ◽

Yu Li ◽

Feng Wu ◽

Ying Bai ◽

Chuan Wu

Keyword(s):

Coulombic Efficiency ◽

Sodium Ion ◽

Carbon Anode ◽

Sodium Ion Batteries ◽

Hard Carbon ◽

Initial Coulombic Efficiency

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Encapsulating Sulfides into Tridymite/Carbon Reactors Enables Stable Sodium Ion Conversion/Alloying Anode with High Initial Coulombic Efficiency Over 89%

Advanced Functional Materials ◽

10.1002/adfm.202009598 ◽

2021 ◽

pp. 2009598

Author(s):

Yani Liu ◽

Linpo Li ◽

Renming Zhan ◽

Maowen Xu ◽

Jian Jiang ◽

...

Keyword(s):

Coulombic Efficiency ◽

Sodium Ion ◽

Initial Coulombic Efficiency

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Decoupling the origins of irreversible coulombic efficiency in anode-free lithium metal batteries

Nature Communications ◽

10.1038/s41467-021-21683-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Chen-Jui Huang ◽

Balamurugan Thirumalraj ◽

Hsien-Chu Tao ◽

Kassie Nigus Shitaw ◽

Hogiartha Sutiono ◽

...

Keyword(s):

Coulombic Efficiency ◽

Rate Capability ◽

Reversible Capacity ◽

Data Interpretation ◽

Lithium Metal ◽

Safety Hazards ◽

Practical Applications ◽

Lithium Metal Batteries ◽

Metallic Lithium ◽

Other Information

AbstractAnode-free lithium metal batteries are the most promising candidate to outperform lithium metal batteries due to higher energy density and reduced safety hazards with the absence of metallic lithium anode during initial cell fabrication. In general, researchers report capacity retention, reversible capacity, or rate capability of the cells to study the electrochemical performance of anode-free lithium metal batteries. However, evaluating the behavior of batteries from limited aspects may easily overlook other information hidden deep inside the meretricious results or even lead to misguided data interpretation. In this work, we present an integrated protocol combining different types of cell configuration to determine various sources of irreversible coulombic efficiency in anode-free lithium metal cells. The decrypted information from the protocol provides an insightful understanding of the behaviors of LMBs and AFLMBs, which promotes their development for practical applications.

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Determination of Flavonoids Compounds of Three Species and Different Harvesting Periods in Crataegi folium Based on LC-MS/MS

Molecules ◽

10.3390/molecules26061602 ◽

2021 ◽

Vol 26 (6) ◽

pp. 1602

Author(s):

Ya-Ping Guo ◽

Hong Yang ◽

Ya-Li Wang ◽

Xiao-Xiang Chen ◽

Ke Zhang ◽

...

Keyword(s):

Quantitative Analysis ◽

Qualitative Analysis ◽

Quantitative Method ◽

Total Content ◽

Qualitative And Quantitative Analysis ◽

Pharmacological Activities ◽

Time Saving ◽

Qualitative And Quantitative ◽

First Time

Crataegi folium have been used as medicinal and food materials worldwide due to its pharmacological activities. Although the leaves of Crataegus songorica (CS), Crataegus altaica (CA) and Crataegus kansuensis (CK) have rich resources in Xinjiang, China, they can not provide insights into edible and medicinal aspects. Few reports are available on the qualitative and quantitative analysis of flavonoids compounds of their leaves. Therefore, it is necessary to develop efficient methods to determine qualitative and quantitative flavonoids compounds in leaves of CS, CA and CK. In the study, 28 unique compounds were identified in CS versus CK by qualitative analysis. The validated quantitative method was employed to determine the content of eight flavonoids of the leaves of CS, CA and CK within 6 min. The total content of eight flavonoids was 7.8–15.1 mg/g, 0.1–9.1 mg/g and 4.8–10.7 mg/g in the leaves of CS, CA and CK respectively. Besides, the best harvesting periods of the three species were from 17th to 26th September for CS, from 30th September to 15th October for CA and CK. The validated and time-saving method was successfully implemented for the analysis of the content of eight flavonoids compounds in CS, CA and CK for the first time.

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A Novel Cobalt Metallopolymer with Redox-Matched Conjugated Organic Backbone via Electropolymerization of a Readily Available N4 Cobalt Complex

Polymers ◽

10.3390/polym13101667 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1667

Author(s):

Mikhail Karushev

Keyword(s):

Redox Reactions ◽

Repeat Unit ◽

Cobalt Complex ◽

Radical Cations ◽

Electrochemical Quartz Crystal Microbalance ◽

Practical Applications ◽

Sensing Applications ◽

Novel Approach ◽

Redox Switching

Fast and reversible cobalt-centered redox reactions in metallopolymers are the key to using these materials in energy storage, electrocatalytic, and sensing applications. Metal-centered electrochemical activity can be enhanced via redox matching of the conjugated organic backbone and cobalt centers. In this study, we present a novel approach to redox matching via modification of the cobalt coordination site: a conductive electrochemically active polymer was electro-synthesized from [Co(Amben)] complex (Amben = N,N′-bis(o-aminobenzylidene)ethylenediamine) for the first time. The poly-[Co(Amben)] films were investigated by cyclic voltammetry, electrochemical quartz crystal microbalance (EQCM), in situ UV‑vis-NIR spectroelectrochemistry, and in situ conductance measurements between −0.9 and 1.3 V vs. Ag/Ag+. The polymer displayed multistep redox processes involving reversible transfer of the total of 1.25 electrons per repeat unit. The findings indicate consecutive formation of three redox states during reversible electrochemical oxidation of the polymer film, which were identified as benzidine radical cations, Co(III) ions, and benzidine di-cations. The Co(II)/Co(III) redox switching is retained in the thick polymer films because it occurs at potentials of high polymer conductivity due to the optimum redox matching of the Co(II)/Co(III) redox pair with the organic conjugated backbone. It makes poly-[Co(Amben)] suitable for various practical applications based on cobalt-mediated redox reactions.

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