scholarly journals Interfacial reactions in lithia-based cathodes depending on the binder in the electrode and salt in the electrolyte

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Hee Jeong Im ◽  
Yong Joon Park
Keyword(s):  
Interfacial Layer ◽  
Redox Reactions ◽  
Polyvinylidene Fluoride ◽  
High Stability ◽  
Side Reaction ◽  
Side Reactions ◽  
Cyclic Performance ◽  
Subsequent Reaction ◽  
Fluoride Ions ◽  
Salt Forms

AbstractLithia (Li2O)-based cathodes, utilizing oxygen redox reactions for obtaining capacity, exhibit higher capacity than commercial cathodes. However, they are highly reactive owing to superoxides formed during charging, and they enable more active parasitic (side) reactions at the cathode/electrolyte and cathode/binder interfaces than conventional cathodes. This causes deterioration of the electrochemical performance limiting commercialization. To address these issues, the binder and salt for electrolyte were replaced in this study to reduce the side reaction of the cells containing lithia-based cathodes. The commercially used polyvinylidene fluoride (PVDF) binder and LiPF6 salt in the electrolyte easily generate such reactions, and the subsequent reaction between PVDF and LiOH (from decomposition of lithia) causes slurry gelation and agglomeration of particles in the electrode. Moreover, the fluoride ions from PVDF promote side reactions, and LiPF6 salt forms POF3 and HF, which cause side reactions owing to hydrolysis in organic solvents containing water. However, the polyacrylonitrile (PAN) binder and LiTFSI salt decrease these side reactions owing to their high stability with lithia-based cathode. Further, thickness of the interfacial layer was reduced, resulting in decreased impedance value of cells containing lithia-based cathodes. Consequently, for the same lithia-based cathodes, available capacity and cyclic performance were increased owing to the effects of PAN binder and LiTFSI salt in the electrolyte.

scholarly journals Interfacial reactions in lithia-based cathodes depending on the binder in the electrode and salt in the electrolyte

2021 ◽  
Author(s):  
Hee Jeong Im ◽  
Yong Joon Park
Keyword(s):  
Interfacial Layer ◽  
Redox Reactions ◽  
Polyvinylidene Fluoride ◽  
High Stability ◽  
Side Reaction ◽  
Side Reactions ◽  
Cyclic Performance ◽  
Subsequent Reaction ◽  
Fluoride Ions ◽  
Salt Forms

Abstract Lithia (Li2O)-based cathodes, utilizing oxygen redox reactions for obtaining capacity, exhibit higher capacity than commercial cathodes. However, they are highly reactive owing to superoxides formed during charging, and they enable more active parasitic (side) reactions at the cathode/electrolyte and cathode/binder interfaces than conventional cathodes. This causes deterioration of the electrochemical performance limiting commercialization. To address these issues, the binder and salt for electrolyte were replaced in this study to reduce the side reaction of the cells containing lithia-based cathodes. The commercially used polyvinylidene fluoride (PVDF) binder and LiPF6 salt in the electrolyte easily generate such reactions, and the subsequent reaction between PVDF and LiOH (from decomposition of lithia) causes slurry gelation and agglomeration of particles in the electrode. Moreover, the fluoride ions from PVDF promote side reactions, and LiPF6 salt forms POF3 and HF, which cause side reactions owing to hydrolysis in organic solvents containing water. However, the polyacrylonitrile (PAN) binder and LiTFSI salt decrease these side reactions owing to their high stability with lithia-based cathode. Further, thickness of the interfacial layer was reduced, resulting in decreased impedance value of cells containing lithia-based cathodes. Consequently, for the same lithia-based cathodes, available capacity and cyclic performance were increased owing to the effects of PAN binder and LiTFSI salt in the electrolyte.

Energetic Control of Redox-Active Polymers Towards Safe Organic Bioelectronic Materials

2019 ◽  
Author(s):  
Alexander Giovannitti ◽  
Reem B. Rashid ◽  
Quentin Thiburce ◽  
Bryan D. Paulsen ◽  
Camila Cendra ◽  
...  
Keyword(s):  
Molecular Oxygen ◽  
Organic Semiconductors ◽  
Side Reaction ◽  
Semiconducting Polymers ◽  
Side Reactions ◽  
Redox Active ◽  
Donor Acceptor ◽  
Electrochemical Devices ◽  
Biological Environment ◽  
Device Operation

<p>Avoiding faradaic side reactions during the operation of electrochemical devices is important to enhance the device stability, to achieve low power consumption, and to prevent the formation of reactive side‑products. This is particularly important for bioelectronic devices which are designed to operate in biological systems. While redox‑active materials based on conducting and semiconducting polymers represent an exciting class of materials for bioelectronic devices, they are susceptible to electrochemical side‑reactions with molecular oxygen during device operation. We show that this electrochemical side reaction yields hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), a reactive side‑product, which may be harmful to the local biological environment and may also accelerate device degradation. We report a design strategy for the development of redox-active organic semiconductors based on donor-acceptor copolymers that prevent the formation of H<sub>2</sub>O<sub>2</sub> during device operation. This study elucidates the previously overlooked side-reactions between redox-active conjugated polymers and molecular oxygen in electrochemical devices for bioelectronics, which is critical for the operation of electrolyte‑gated devices in application-relevant environments.</p>

scholarly journals Dehydrogenation of Propane to Propylene Using Promoter-Free Hierarchical Pt/Silicalite-1 Nanosheets

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 174 ◽  
Author(s):  
Wannaruedee Wannapakdee ◽  
Thittaya Yutthalekha ◽  
Pannida Dugkhuntod ◽  
Kamonlatth Rodponthukwaji ◽  
Anawat Thivasasith ◽  
...  
Keyword(s):  
Hierarchical Structures ◽  
Pt Nanoparticles ◽  
Side Reaction ◽  
Diffusion Path ◽  
Side Reactions ◽  
Complete Suppression ◽  
Metal Support Interaction ◽  
Defect Sites ◽  
Propylene Yield ◽  
Propylene Production

Propane dehydrogenation (PDH) is the extensive pathway to produce propylene, which is as a very important chemical building block for the chemical industry. Various catalysts have been developed to increase the propylene yield over recent decades; however, an active site of monometallic Pt nanoparticles prevents them from achieving this, due to the interferences of side-reactions. In this context, we describe the use of promoter-free hierarchical Pt/silicalite-1 nanosheets in the PDH application. The Pt dispersion on weakly acidic supports can be improved due to an increase in the metal-support interaction of ultra-small metal nanoparticles and silanol defect sites of hierarchical structures. This behavior leads to highly selective propylene production, with more than 95% of propylene selectivity, due to the complete suppression of the side catalytic cracking. Moreover, the oligomerization as a side reaction is prevented in the presence of hierarchical structures due to the shortening of the diffusion path length.

Organoaluminium compounds. VII. The reactions of organoaluminium compounds with phenylacetylene

1964 ◽  
Vol 17 (11) ◽  
pp. 1229 ◽  
Author(s):  
T Mole ◽  
JR Surtees
Keyword(s):  
Triple Bond ◽  
Side Reaction ◽  
Similar Process ◽  
Side Reactions ◽  
Crystalline Solids ◽  
Ethereal Solution ◽  
Presence And Absence

The reactions of trimethyl-, triethyl-, tripropyl-, tri-isobutyl-, and triphenylaluminium with phenylacetylene in the presence and absence of benzene or toluene have been studied. In every case phenylethynylaluminium compounds are formed. Dimethyl(phenylethynyl)aluminium and diphenyl(phenylethynyl)aluminium are crystalline solids. The former compound disproportionates partially in ethereal solution. Side reactions competing with the formation of phenylethynylaluminium compounds are also observed. Triethylaluminium and tripropylaluminium add to phenylacetylene to give PhC(AlR2)=CHR (R = Et, Pr), but these alkenylaluminium compounds metallate further phenylacetylene and are so transformed to alkenes. A similar process occurs in the reaction with triphenylaluminium, but in this case both possible products of cis addition are observed. Tri-isobutylaluminium yields phenylethenyl compounds by reduction of the triple bond in the principal side reaction.

scholarly journals OxymaPure Coupling Reagents: Beyond Solid-Phase Peptide Synthesis

Synthesis ◽  
2020 ◽  
Vol 52 (21) ◽  
pp. 3189-3210
Author(s):  
Ayman El-Faham ◽  
Fernando Albericio ◽  
Srinivasa Rao Manne ◽  
Beatriz G. de la Torre
Keyword(s):  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Coupling Efficiency ◽  
Side Reaction ◽  
Solution Phase ◽  
Amide Bond ◽  
Side Reactions ◽  
Phosphonium Salts ◽  
Coupling Reagents ◽  
Peptide Chemistry

AbstractOxymaPure [ethyl 2-cyano-2-(hydroxyimino)acetate] is an exceptional reagent with which to suppress racemization and enhance coupling efficiency during amide bond formation. The tremendous popularity of OxymaPure has led to the development of several Oxyma-based reagents. OxymaPure and its derived reagents are widely used in solid- and solution-phase peptide chemistry. This review summarizes the recent developments and applications of OxymaPure and Oxyma-based reagents in peptide chemistry, in particular in solution-phase chemistry. Moreover, the side reaction associated with OxymaPure is also discussed.1 Introduction2 Oxyma-Based Coupling Reagents2.1 Aminium/Uronium Salts of OxymaPure2.2 Phosphonium Salts of OxymaPure2.3 Oxyma-Based Phosphates2.4 Sulfonate Esters of OxymaPure2.5 Benzoate Esters of OxymaPure2.6 Carbonates of OxymaPure Derivatives3 OxymaPure Derivatives4 Other Oxime-Based Additives and Coupling Reagents5 Side Reactions Using OxymaPure Derivatives6 Conclusion7 List of Abbreviations

Energetic Control of Redox-Active Polymers Towards Safe Organic Bioelectronic Materials

2019 ◽  
Author(s):  
Alexander Giovannitti ◽  
Reem B. Rashid ◽  
Quentin Thiburce ◽  
Bryan D. Paulsen ◽  
Camila Cendra ◽  
...  
Keyword(s):  
Molecular Oxygen ◽  
Organic Semiconductors ◽  
Side Reaction ◽  
Semiconducting Polymers ◽  
Side Reactions ◽  
Redox Active ◽  
Donor Acceptor ◽  
Electrochemical Devices ◽  
Biological Environment ◽  
Device Operation

<p>Avoiding faradaic side reactions during the operation of electrochemical devices is important to enhance the device stability, to achieve low power consumption, and to prevent the formation of reactive side‑products. This is particularly important for bioelectronic devices which are designed to operate in biological systems. While redox‑active materials based on conducting and semiconducting polymers represent an exciting class of materials for bioelectronic devices, they are susceptible to electrochemical side‑reactions with molecular oxygen during device operation. We show that this electrochemical side reaction yields hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), a reactive side‑product, which may be harmful to the local biological environment and may also accelerate device degradation. We report a design strategy for the development of redox-active organic semiconductors based on donor-acceptor copolymers that prevent the formation of H<sub>2</sub>O<sub>2</sub> during device operation. This study elucidates the previously overlooked side-reactions between redox-active conjugated polymers and molecular oxygen in electrochemical devices for bioelectronics, which is critical for the operation of electrolyte‑gated devices in application-relevant environments.</p>

scholarly journals Interaction of Hydride Silica Surfaces with N-Vinyl-2-Pyrrolidone

2000 ◽  
Vol 18 (1) ◽  
pp. 65-74
Author(s):  
L.A. Belyakova ◽  
A.M. Varvarin
Keyword(s):  
Surface Layer ◽  
Chemical Bonding ◽  
Solid Phase ◽  
Side Reaction ◽  
Thermal Polymerization ◽  
Side Reactions ◽  
Silicon Hydride ◽  
Metallic Platinum ◽  
Silica Surfaces ◽  
Catalytic Hydrosilylation

The solid-phase thermal and catalytic hydrosilylation of N-vinyl-2-pyrrolidone on the surface of hydride silicas has been studied. It was established that thermal polymerization of N-vinyl-2-pyrrolidone occurs as a side reaction during the thermal hydrosilylation of N-vinyl-2-pyrrolidone. It has also been found that the interaction of silicon hydride groups with water and propan-2-ol, as well as the formation of metallic platinum occur as side reactions during the catalytic hydrosilylation of N-vinyl-2-pyrrolidone on the surface of hydride silicas. Thermal hydrosilylation of N-vinyl-2-pyrrolidone in the absence of a catalyst and solvent is much preferred for the chemical bonding of N-vinyl-2-pyrrolidone in the surface layer of hydride silicas.

The isomerization of ammonium cyanates. II. The kinetics of isomerization of ammonium and alkylammonium cyanates in dimethyl sulphoxide-water mixtures

1977 ◽  
Vol 30 (4) ◽  
pp. 903
Author(s):  
KJ Hall ◽  
DW Watts
Keyword(s):  
Side Reaction ◽  
Dimethyl Sulphoxide ◽  
Side Reactions ◽  
Solvent Mixtures ◽  
Kinetics Of ◽  
Reaction In Water

The kinetics of the isomerizations of ammonium, methylammonium and ethylammonium cyanates to urea, methylurea and ethylurea have been studied in aqueous dimethyl sulphoxide over the range 0-100% dimethyl sulphoxide. Side reactions occur at all solvent compositions and urea formation accounts for only between 65% and 90% of products. The side reaction in water produces carbonate and in dimethyl sulphoxide biuret or alkyl-substituted biurets. The proportion of each of these products in solvent mixtures has not been determined.

scholarly journals ABC-Type Triblock Copolyacrylamides via Copper-Mediated Reversible Deactivation Radical Polymerization

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 116
Author(s):  
Fehaid M. Alsubaie ◽  
Othman Y. Alothman ◽  
Hassan Fouad ◽  
Abdel-Hamid I. Mourad
Keyword(s):  
Radical Polymerization ◽  
Triblock Copolymers ◽  
Side Reaction ◽  
Side Reactions ◽  
One Pot ◽  
Functional Monomers ◽  
Reversible Deactivation ◽  
Living Nature ◽  
Reversible Deactivation Radical Polymerization ◽  
High Degree

The aqueous Cu(0)-mediated reversible deactivation radical polymerization (RDRP) of triblock copolymers with two block sequences at 0.0 °C is reported herein. Well-defined triblock copolymers initiated from PHEAA or PDMA, containing (A) 2-hydroxyethyl acrylamide (HEAA), (B) N-isopropylacrylamide (NIPAM) and (C) N, N-dimethylacrylamide (DMA), were synthesized. The ultrafast one-pot synthesis of sequence-controlled triblock copolymers via iterative sequential monomer addition after full conversion, without any purification steps throughout the monomer additions, was performed. The narrow dispersities of the triblock copolymers proved the high degree of end-group fidelity of the starting macroinitiator and the absence of any significant undesirable side reactions. Controlled chain length and extremely narrow molecular weight distributions (dispersity ~ 1.10) were achieved, and quantitative conversion was attained in as little as 52 min. The full disproportionation of CuBr in the presence of Me6TREN in water prior to both monomer and initiator addition was crucially exploited to produce a well-defined ABC-type triblock copolymer. In addition, the undesirable side reaction that could influence the living nature of the system was investigated. The ability to incorporate several functional monomers without affecting the living nature of the polymerization proves the versatility of this approach.

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