Effect of CsF-concentration on electrolytic conductivity, viscosity and anodic reaction of nickel electrode in (CH3)3N-CsF–HF system at room temperature

Tasaka, Akimasa; Nakanishi, Kenta; Masuda, Noriaki; Nakai, Takaaki; Ikeda, Kazuhiko; Momota, Kunitaka; Saito, Morihiro; Inaba, Masaaki

doi:10.1016/j.electacta.2011.01.031

Cited by 12 publications

(9 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[ 17 ] However, all the above results solely depended on X‐ray photoelectron spectroscopy (XPS), which may lead to wrong deconvolution of the spectra without consideration of the binding energy shift of the metal fluorine bonds from a lower oxidation state. [ 18 ] So the detailed regulation mechanism on which fluorine substitution enhancing the electrochemical performance of the cathode materials in SIBs is still obscure. In addition, the substitution position of fluorine in the sodium cathode materials (surface or bulk) requires further clarification, in particular given the fact that it is difficult to dope fluorine into the bulk of LiMO 2 layered cathodes.…”

Section: Introductionmentioning

confidence: 99%

Insights into the Enhanced Cycle and Rate Performances of the F‐Substituted P2‐Type Oxide Cathodes for Sodium‐Ion Batteries

Tan

Moon

et al. 2020

Advanced Energy Materials

View full text Add to dashboard Cite

A series of F‐substituted Na2/3Ni1/3Mn2/3O2−xFx (x = 0, 0.03, 0.05, 0.07) cathode materials have been synthesized and characterized by solid‐state 19F and 23Na NMR, X‐ray photoelectron spectroscopy, and neutron diffraction. The underlying charge compensation mechanism is systematically unraveled by X‐ray absorption spectroscopy and electron energy loss spectroscopy (EELS) techniques, revealing partial reduction from Mn4+ to Mn3+ upon F‐substitution. It is revealed that not only Ni but also Mn participates in the redox reaction process, which is confirmed for the first time by EELS techniques, contributing to an increase in discharge specific capacity. The detailed structural transformations are also revealed by operando X‐ray diffraction experiments during the intercalation and deintercalation process of Na+, demonstrating that the biphasic reaction is obviously suppressed in the low voltage region via F‐substitution. Hence, the optimized sample with 0.05 mol f.u.−1 fluorine substitution delivers an ultrahigh specific capacity of 61 mAh g−1 at 10 C after 2000 cycles at 30 °C, an extraordinary cycling stability with a capacity retention of 75.6% after 2000 cycles at 10 C and 55 °C, an outstanding full battery performance with 89.5% capacity retention after 300 cycles at 1 C. This research provides a crucial understanding of the influence of F‐substitution on the crystal structure of the P2‐type materials and opens a new avenue for sodium‐ion batteries.

show abstract

Section: Introductionmentioning

confidence: 99%

Insights into the Enhanced Cycle and Rate Performances of the F‐Substituted P2‐Type Oxide Cathodes for Sodium‐Ion Batteries

Tan

Moon

et al. 2020

Advanced Energy Materials

View full text Add to dashboard Cite

show abstract

“…The earlier literature works carried out on the anodic polarisation of Ni electrode in the fluoride melt, clearly showed that the electrochemical fluorination reaction took place in between 4.0 and 8.0 V versus Ag/Ag ? , which was associated with two anodic processes namely electrocatalytic oxidation of Ni(II) fluoride to Ni(III) or Ni(IV) and fluorine evolution reaction, respectively [6][7][8]. Furthermore, the above voltammetric analysis revealed that the potential region of NiF 2 film formation and the above plateau current are well separated by a value of 4.0 V versus Ag/Ag ?…”

Section: Metal Dissolution By Aas Studiesmentioning

confidence: 90%

“…[6][7][8]. On the other hand, the addition of a depolariser, namely trialkylamine during the ECPF of octylsulphurylfluoride reveals that the electrolysis can be carried out at sufficiently high-current densities for a longer time and the yield of the final product also increases [9].…”

Section: Introductionmentioning

confidence: 96%

Influence of triethylamine on the anodic dissolution characteristics of Ni, Cu and their alloys in non-aqueous solvents containing fluoride media: voltammetric and surface morphologic study

et al. 2012

View full text Add to dashboard Cite

Multisweep cyclic voltammetric (CV) responses of nickel, copper, Monel and nickel-copper alloy had been extensively studied and compared in different nonaqueous solvents, such as acetonitrile (AN), propylene carbonate (PC) and sulpholane-containing anhydrous hydrogen fluoride (AHF) medium in the absence and the presence of triethylamine (Et 3 N). The quantity of dissolution and surface morphological transformation on the electrodes as a result of anodic polarisation were investigated by means of atomic absorption spectroscopy and scanning electron microscopy (SEM), respectively. The CV study indicates that Ni, Cu and their alloys are highly unstable in AN/AHF medium. Surface morphology of Ni after polarisation in this medium reveals the generation of number of pits, whereas the evolution of small crystallites of CuF 2 is noted on the polarised alloy material, as evidenced by SEM pictures. The dissolution characteristics decrease significantly in PC/AHF medium and become low in sulpholanecontaining fluoride medium on the four electrodes. The relative solubility of metal fluoride film in the three solvents increases in the order: sulpholane \ PC \ AN. The voltammograms suggest that addition of Et 3 N (0.5 M) to AN-and PC-containing AHF medium helps both in maintaining uniform dissolution and generating compact fluoride film on the electrode surface. The addition of Et 3 N to AHF/sulpholane medium shows only little influence in improving the electrocatalytic oxidation process.

show abstract

“…Thus, it is considered that the current efficiency for NF 3 formation was increased by addition of CsF. Table 2 Reversible potentials (vs. SHE) for formation of nickel oxide and nickel fluoride [4,5] ECS Transactions, 41 (17) 69-74 (2012)…”

Section: Electrolytic Production Of Nf 3 and Corrosion Studymentioning

confidence: 99%

Effect of Addition of Alkali Metal Fluoride to a Molten NH₄F-HF System on Current Efficiency for NF₃ Formation and Nickel Anode Consumption

et al. 2012

Self Cite

View full text Add to dashboard Cite

The current efficiency for NF 3 formation and the current loss caused by Ni dissolution were investigated in electrolysis of the NH 4 F·2HF melts with and without alkali metal fluorides such as CsF, KF, and LiF. The addition of CsF to the melt was most effective for increasing the NF 3 current efficiency. In contrast, the addition of KF to the melt decreased the current efficiency for NF 3 formation and increased the current loss caused by Ni dissolution. The SEM observation and XRD analysis revealed that the oxidized layer formed on nickel in the melt containing LiF or CsF was composed of NiF 2 with highly oxidized nickel fluoride. On the other hand, the oxidized layer in the melt containing KF was composed of only KNiF 3 , and was very brittle. Therefore, it is concluded that KF is detrimental to the nickel anode and highly oxidized nickel fluoride may relate to the NF 3 current efficiency.፧

show abstract

Effect of CsF-concentration on electrolytic conductivity, viscosity and anodic reaction of nickel electrode in (CH3)3N-CsF–HF system at room temperature

Cited by 12 publications

References 15 publications

Insights into the Enhanced Cycle and Rate Performances of the F‐Substituted P2‐Type Oxide Cathodes for Sodium‐Ion Batteries

Insights into the Enhanced Cycle and Rate Performances of the F‐Substituted P2‐Type Oxide Cathodes for Sodium‐Ion Batteries

Influence of triethylamine on the anodic dissolution characteristics of Ni, Cu and their alloys in non-aqueous solvents containing fluoride media: voltammetric and surface morphologic study

Effect of Addition of Alkali Metal Fluoride to a Molten NH₄F-HF System on Current Efficiency for NF₃ Formation and Nickel Anode Consumption

Contact Info

Product

Resources

About

Effect of CsF-concentration on electrolytic conductivity, viscosity and anodic reaction of nickel electrode in (CH3)3N-CsF–HF system at room temperature

Cited by 12 publications

References 15 publications

Insights into the Enhanced Cycle and Rate Performances of the F‐Substituted P2‐Type Oxide Cathodes for Sodium‐Ion Batteries

Insights into the Enhanced Cycle and Rate Performances of the F‐Substituted P2‐Type Oxide Cathodes for Sodium‐Ion Batteries

Influence of triethylamine on the anodic dissolution characteristics of Ni, Cu and their alloys in non-aqueous solvents containing fluoride media: voltammetric and surface morphologic study

Effect of Addition of Alkali Metal Fluoride to a Molten NH4F-HF System on Current Efficiency for NF3 Formation and Nickel Anode Consumption

Contact Info

Product

Resources

About

Effect of Addition of Alkali Metal Fluoride to a Molten NH₄F-HF System on Current Efficiency for NF₃ Formation and Nickel Anode Consumption