Synthesis, Structures and Electrochemical Properties of Lithium 1,3,5-Benzenetricarboxylate Complexes

Cheng, Pei Chi; Li, Bing Han; Tseng, Feng Shuen; Liang, Po Ching; Lin, Chia Her; Liu, Wei‐Ren

doi:10.3390/polym11010126

Cited by 4 publications

(5 citation statements)

References 44 publications

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“…The resulting pH values are very approximate, but they do indicate that water molecules in these complexes can result in a highly acidic solution. These results suggest that the origin of the acidity of LiTFSI/H 2 O electrolytes is not due to the enhanced proton transfer from water molecules of the primary Li + solvation sphere to bulk water molecules, but rather the deprotonated water molecules bridged over at least two Li + ions 35 as part of the multimeric salt structures, which would only become possible at extreme salt concentrations. Hence, the origin of this unusual acidity can be inferred as part of long-range cluster evolution, where water molecules bonded to two or more LiTFSI molecules can generate hydroxide through a deprotonation reaction.…”

Section: ■ Results and Discussionmentioning

confidence: 90%

Origin of Unusual Acidity and Li⁺ Diffusivity in a Series of Water-in-Salt Electrolytes

et al. 2020

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Superconcentrated aqueous electrolytes ("water-in-salt" electrolytes, or WiSEs) enable various aqueous battery chemistries beyond the voltage limits imposed by the Pourbaix diagram of water. However, their detailed structural and transport properties remain unexplored and could be better understood through added studies.Here, we report on our observations of strong acidity (pH 2.4) induced by lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) at superconcentration (at 20 mol/kg). Multiple nuclear magnetic resonance (NMR) and pulsed-field gradient (PFG) diffusion NMR experiments, density functional theory (DFT) calculations, and molecular dynamics (MD) simulations reveal that such acidity originates from the formation of nanometric ion-rich structures. The experimental and simulation results indicate the separation of water-rich and ion-rich domains at salt concentrations ≥5 m and the acidity arising therefrom is due to deprotonation of water molecules in the ion-rich domains. As such, the ion-rich domain is composed of hydrophobic −CF 3 (of TFSI − ) and hydrophilic hydroxyl (OH − ) groups. At 20 m concentration, the tortuosity and radius of water diffusion channels are estimated to be ∼10 and ∼1 nm, respectively, which are close to values obtained from hydrated Nafion membranes that also have hydrophobic polytetrafluoroethylene (PTFE) backbones and hydrophilic channels consisting of SO 3 − ion cluster networks providing for the transport of ions and water. Thus, we have discovered the structural similarity between WiSE and hydrated Nafion membranes on the nanometer scale.

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Section: ■ Results and Discussionmentioning

confidence: 90%

Origin of Unusual Acidity and Li⁺ Diffusivity in a Series of Water-in-Salt Electrolytes

et al. 2020

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“…The XRD patterns of Li‐BTC shown in Figure S2b, Supporting Information are in good agreement with the reported XRD patterns of the lithiated organic molecular salt of 1,3,5‐H 3 BTC. [ 35 ]…”

Section: Resultsmentioning

confidence: 99%

“…A similar role may be speculated for TPA and Li‐BTC as coating substrates. However, we must mention that Li‐BTC can participate in reversible Li‐insertion/de‐insertion in the potential window of 0.01–3.0 V. [ 35 ]…”

Section: Resultsmentioning

confidence: 99%

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Stabilizing High‐Voltage LiNi_0.5Mn_1.5O₄ Cathodes for High Energy Rechargeable Li Batteries by Coating With Organic Aromatic Acids and Their Li Salts

et al. 2022

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z O 2 (NCA) cathode materials. [1,2] However, LFP suffers from low electric conductivity and relatively low discharge potential, [3] while the decreasing abundance, increased cost, and severe toxicity issues of cobalt and nickel raise a big question for the broad application of LCO/NCM/NCA-based Li batteries. [4] Surprisingly, commercialization of Cofree high-voltage cathode materials such as LiNi 0.5 Mn 1.5 O 4 (LNMO) with several outstanding properties, including 3D channels for high rate Li-ion diffusion, [5] high operating potential (≈4.7-4.8 V) with moderately high energy density (up to 650 Wh kg −1 ), [6,7] better thermal stability, [8] and relatively low cost, is comparatively behind and underrated. We believe that these outstanding inherent properties of high-voltage spinel LNMO cathodes can make them economical and promising for advanced LIB technologies. [9] Here, our primary aim was to address the two challenging issues of LNMO cathodes: limited cycle life and fast capacity degradation, especially at elevated temperatures. These critical issues typically originate from structural and chemical instability operating at higher potentials in Li batteries electrolyte solutions. During Li + intercalation/de-intercalation, Li-rich and Li-poor domains coexist, which leads to problems such as phase boundary dislocations, stress at grain boundaries, and pulverization of particles. [10] The gradual capacity drop during prolonged cycling is also associated with lattice parameter changes during LNMO's two-phase domains (Li-rich and Li-poor) formation and reduction in the octahedral MnO 6 distortion. [11] Moreover, Mn 2+ ions dissolution from the cathode's surface due to disproportionation reaction: 2Mn 3+ →Mn 4+ + Mn 2+ and Mn 3 O 4 -like phase formation during cycling further introduce structural instability/integrity associated with capacity drop. [12,13] In addition, thick poly(ethylene carbonate (EC))-rich cathode-electrolyte solutions interphase (CEI) formation while operating at the high potential in typical EC-based electrolyte solution causes high cells' impedance. [14] In addition, de-lithiated LNMO may catalyze electrolyte solution decomposition that induces self-discharge in the cells. [15,16] Furthermore, nickel Here, three types of surface coatings based on adsorption of organic aromatic acids or their Li salts are applied as functional coating substrates to engineer the surface properties of high voltage LiNi 0.5 Mn 1.5 O 4 (LNMO) spinel cathodes. The materials used as coating include 1,3,5-benzene-tricarboxylic acid (trimesic acid [TMA]), its Li-salt, and 1,4-benzene-dicarboxylic acid (terephthalic acid). The surface coating involves simple ethanol liquidphase mixing and low-temperature heat treatment under nitrogen flow. In typical comparative studies, TMA-coated (3-5%) LNMO cathodes deliver >90% capacity retention after 400 cycles with significantly improved rate performance in Li-coin cells at 30 °C compared to uncoated material with capacity retention of ≈40%. The cathode coating also prevents th...

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“…MOFs designed with these ligands exhibit properties and functions that are attractive to researchers due to their rigidity and trifunctional identity [26][27][28]. Even though the BTBA and MTBA systems are at first glance quite similar, their geometries differ markedly.…”

Section: Introductionmentioning

confidence: 99%

New Microporous Lanthanide Organic Frameworks. Synthesis, Structure, Luminescence, Sorption, and Catalytic Acylation of 2-Naphthol

et al. 2020

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New metal-organic frameworks (MOF) with lanthanum(III), cerium(III), neodymium(III), europium(III), gadolinium(III), dysprosium(III), and holmium(III)] and the ligand precursor 1,3,5-tris(4-carboxyphenyl)-2,4,6-trimethylbenzene (H3L) were synthesized under solvothermal conditions. Single crystal x-ray analysis confirmed the formation of three-dimensional frameworks of [LnL(H2O)2]n·xDMF·yH2O for Ln = La, Ce, and Nd. From the nitrogen sorption experiments, the compounds showed permanent porosity with Brunauer-Emmett-Teller (BET) surface areas of about 400 m2/g, and thermal stability up to 500 °C. Further investigations showed that these Ln-MOFs exhibit catalytic activity, paving the way for potential applications within the field of catalysis.

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Synthesis, Structures and Electrochemical Properties of Lithium 1,3,5-Benzenetricarboxylate Complexes

Cited by 4 publications

References 44 publications

Origin of Unusual Acidity and Li⁺ Diffusivity in a Series of Water-in-Salt Electrolytes

Origin of Unusual Acidity and Li⁺ Diffusivity in a Series of Water-in-Salt Electrolytes

Stabilizing High‐Voltage LiNi_0.5Mn_1.5O₄ Cathodes for High Energy Rechargeable Li Batteries by Coating With Organic Aromatic Acids and Their Li Salts

New Microporous Lanthanide Organic Frameworks. Synthesis, Structure, Luminescence, Sorption, and Catalytic Acylation of 2-Naphthol

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Synthesis, Structures and Electrochemical Properties of Lithium 1,3,5-Benzenetricarboxylate Complexes

Cited by 4 publications

References 44 publications

Origin of Unusual Acidity and Li+ Diffusivity in a Series of Water-in-Salt Electrolytes

Origin of Unusual Acidity and Li+ Diffusivity in a Series of Water-in-Salt Electrolytes

Stabilizing High‐Voltage LiNi0.5Mn1.5O4 Cathodes for High Energy Rechargeable Li Batteries by Coating With Organic Aromatic Acids and Their Li Salts

New Microporous Lanthanide Organic Frameworks. Synthesis, Structure, Luminescence, Sorption, and Catalytic Acylation of 2-Naphthol

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Product

Resources

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Origin of Unusual Acidity and Li⁺ Diffusivity in a Series of Water-in-Salt Electrolytes

Origin of Unusual Acidity and Li⁺ Diffusivity in a Series of Water-in-Salt Electrolytes

Stabilizing High‐Voltage LiNi_0.5Mn_1.5O₄ Cathodes for High Energy Rechargeable Li Batteries by Coating With Organic Aromatic Acids and Their Li Salts