Problems Associated with the Electrochemical Reduction of Metal Ions in LiNO3 ‐  KNO 3 and LiClO4 ‐ KClO4 Melts: The Reduction of Nitrato and Perchlorato Complexes

Miles, M. H.; McManis, George E.; Fletcher, A. N.

doi:10.1149/1.2100517

Cited by 9 publications

(4 citation statements)

References 18 publications

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“…15 The LiNO 3 −KNO 3 showed wider electrochemical window at the lower operating temperature than the halides. 44 However, the LiNO 3 −KNO 3 generates exothermic reactions with the Li alloy negative electrodes, which lead to fire disasters. 15 The Li[Tf 2 N] mixtures have wide electrochemical windows of over 5.0 V due to the high oxidation resistance of the Tf 2 N − .…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Investigation of an Intermediate Temperature Molten Lithium Salt Based on Fluorosulfonyl(trifluoromethylsulfonyl)amide as a Solvent-Free Lithium Battery Electrolyte

Kubota¹,

Matsumoto²

2013

J. Phys. Chem. C

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The asymmetric amide anion, such as (fluorosulfonyl)(trifluoromethylsulfonyl)amide (fTfN–), formed intermediate temperature molten lithium salts at 100 °C, which was the lowest among the lithium single molten salts composed of conventional halogenide, nitrate, perchlorate, and perfluoro anions. The molten Li[fTfN] was highly viscous (17 Pa·s at 110 °C, however, it was classified as a good ionic liquid by Walden plot analysis, which indicates the good-dissociation between Li+ and fTfN–. Due to the high transport number of the lithium cation (0.94), the Li[fTfN] behaves as a single lithium-ion conducting material. The Li[fTfN] possesses an electrochemical window (5.0 V) due to the oxidative resistance of the perfluoro anion. The charge and discharge for a conventional composite positive electrode containing LiCoO2 or LiFePO4 was successful. In particular, LiFePO4 showed a high capacity and Coulombic efficiency at 0.1–5 C.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Investigation of an Intermediate Temperature Molten Lithium Salt Based on Fluorosulfonyl(trifluoromethylsulfonyl)amide as a Solvent-Free Lithium Battery Electrolyte

Kubota¹,

Matsumoto²

2013

J. Phys. Chem. C

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“…Anodic dissolution of the CuO deposit would be expected to occur by the reaction with either nitrate CuO + ONO~ -~ Cu(ONO~) § + 112 O~ + 2e- [4] or residual nitrite ion…”

Section: Table I Coulombs Of Charge For Copper Aqueous Deposition (Qd)mentioning

confidence: 99%

“…ble, and the latter is converted quantitatively to superoxide in the presence of oxygen via O~ +O2=20~ [3] This picture is supported by extensive electrochemical data, 7-n electron paramagnetic resonance detection of superoxide, 12 independent manometric measurements of the oxygen uptake associated with reaction 3 above, ~3 and good correlations with similar solid-state data. TM Zambonin '5 also showed that water quantitatively converts superoxide to hydroxide (OH-) within a few hours 2 02 + H20 = 3/2 02 + 2 OH- [4] This, of course, introduces additional electrochemical reactions that would have to be taken into account in wet melts.…”

Section: Electrodeposition Of Mixedmentioning

confidence: 99%

Electrodeposition of Copper Oxide from the Eutectic Sodium‐Potassium Nitrate Melt

Tench

Kendig

Jeanjaquet

1994

J. Electrochem. Soc.

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Copper injected anodically into eutectic Na-K nitrate melt at 300~ is shown to deposit cathodically as cupric oxide (CuO). The dissolved copper is in the +2 oxidation state and apparently forms a nitrate complex that facilitates reduction of nitrate to oxide (and nitrite) at potentials more than a volt positive of that for reduction of the Na/K nitrate species. From these results and literature studies, cathodic metal oxide deposition from nitrate melts appears to be a general phenomenon that could prove to be a practical means of preparing anhydrous metal oxide films.Oxide films are of interest for a variety of practical applications, including corrosion protection, batteries, high temperature superconductors, catalysts, electronic devices, and flat panel displays. In many cases, anhydrous films are required, but oxides produced by electrodeposition from aqueous electrolytes generally are at least partially hydrated. Dehydration can be effected by thermal treatments, but the film quality attained is typically degraded because atomic/molecular rearrangements are involved. This is unfortunate since the electrodeposition approach is ideally suited to coating large areas and irregular substrates and can provide close control over the deposition process. One possibility for directly-electrodepositing anhydrous metal oxides is to use a molten salt solvent.Several studies 1-5 have indicated that oxides of a wide range of metals, rather than the free metals themselves, are deposited from nitrate melts. Since the observed reduction potentials in some cases are up to a volt positive of the potential required for nitrate reduction in the background Na-K nitrate melt, it has been proposed that metal oxide deposition occurs via a nitrate complex, 3-~ i.e., according tofor a divalent cation. Note that rapid nitrate reduction produced by high cathodic polarization in the pure Na-K nitrate melt results in deposition of sodium oxide, but the deposit eventually redissolves. ~ The present work was directed toward demonstrating that metallic oxide deposition from nitrate melts indeed occurs. Because of the technological importance of transition metals, a member of this group, copper, was chosen for study. Some previous workers 6-8 suggested that copper metal itself is deposited, but they did not verify the nature of the deposits produced. In these earlier studies, Cu 2+ was dissolved as either the nitrate (stabilized by addition of KHSQ) or the chloride, and shown to introduce a diffusion-limited reduction wave (Pt electrode) with an onset at about +0.3 V vs. Ag/Ag+. 6.7 Note that the onset voltage was identical whether Cu 2 § was added as the chloride or nitrate, suggesting that the melt species might be the same in either case. Previous work 9'1~ also indicates that metallic Cu spontaneously forms Cu20 in nitrate melts and that passivation, involving formation of CuO, occurs at about -0.1 V vs. Ag/Ag + electrode. Experimental DetailsCell and glove box.--Figure I depicts the molten satt electrochemical cell assembly used in the pr...

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“…Moisture present in the melt was estimated quantitatively by applying the Randles and Sevick equation [13] as Ip = (4.64 × 10 6 /T 1/2 ) n 3/2 AD ½ Cv ½ ( 2 ) The moisture content was found on the order of around 10 -4 M present at 300 0 C. A different explanation has been proposed for interaction of water reduction reaction with nitrate ion reduction. However, complex ion formation [ 14,15] involving water and nitrate ions is the most acceptable one. This can be presented in following steps…”

mentioning

confidence: 99%

Influence of Moisture on the Hot Corrosion of Metals in Nitrate and Sulfate Melts

Singh

2004

MSF

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Electrochemical measurements like potentiodynamic polarization and cyclic voltammetry have been carried in absence ( dried ) and presence of moisture (undried) in (Na, K) NO 3 and (Li, Na, K) 2 SO 4 melts at 300 0 and 550 0 C, respectively on platinum, nickel and iron metals surfaces. The cyclic voltammetry study on iron revealed an increase in the cathodic process for the undried melt in comparison to a dried melt. To ascertain the effect of moisture on hot corrosion, the oxidation rates of iron and nickel were determined by Tafel extrapolation. A proportionate increase in oxidation rates in the presence of moisture in both systems suggests that moisture increases the oxidation reaction of metals. Cyclic voltammetric measurements suggest that the presence of moisture in the melt enhances reduction of the nitrate and sulphate ions, which apparently increases the hot corrosion reaction in the system.

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Problems Associated with the Electrochemical Reduction of Metal Ions in LiNO3 ‐ KNO 3 and LiClO4 ‐ KClO4 Melts: The Reduction of Nitrato and Perchlorato Complexes

Cited by 9 publications

References 18 publications

Investigation of an Intermediate Temperature Molten Lithium Salt Based on Fluorosulfonyl(trifluoromethylsulfonyl)amide as a Solvent-Free Lithium Battery Electrolyte

Investigation of an Intermediate Temperature Molten Lithium Salt Based on Fluorosulfonyl(trifluoromethylsulfonyl)amide as a Solvent-Free Lithium Battery Electrolyte

Electrodeposition of Copper Oxide from the Eutectic Sodium‐Potassium Nitrate Melt

Influence of Moisture on the Hot Corrosion of Metals in Nitrate and Sulfate Melts

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